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Oil-tempering  the  lining  of  a  Big  Gun  (See  page  76) 


INVENTIONS  OF  THE 
GREAT  WAR 


INVENTIONS  OF  THE 
GREAT  WAR 


BY 

A.  RUSSELL  BOND 

MANAGING  EDITOR  OF  "SCIENTIFIC  AMERICAN/' 

AUTHOR  OF  "ON  THE  BATTLE-FRONT 

OF  ENGINEERING,"  ETC. 


WITH  MANY 
ILLUSTRATIONS 


NEW  YORK 
THE  CENTURY  CO. 

1919 


Copyright,  1918,  1919,  by 
THE  CENTUBY  Co. 


Published,  June,  1919 


is 


PREFACE 

The  great  World  War  was  more  than  two- 
thirds  over  when  America  entered  the  struggle, 
and  yet  in  a  sense  this  country  was  in  the  war 
from  its  very  beginning.  Three  great  inven- 
tions controlled  the  character  of  the  fighting 
and  made  it  different  from  any  other  the  world 
has  ever  seen.  These  three  inventions  were 
American.  The  submarine  was  our  invention ; 
it  carried  the  war  into  the  «sea.  The  airplane 
was  an  American  invention ;  it  carried  the  war 
into  the  sky.  We  invented  the  machine  gun;  it 
drove  the  war  into  the  ground. 

It  is  not  my  purpose  to  boast  of  American 
genius  but,  rather,  to  show  that  we  entered  the 
war  with  heavy  responsibilities.  The  inven- 
tions we  had  given  to  the  world  had  been  de- 
veloped marvelously  in  other  lands.  Further- 
more they  were  in  the  hands  of  a  determined 
and  unscrupulous  foe,  and  we  found  before  us 
the  task  of  overcoming  the  very  machines  that 
we  had  created.  Yankee  ingenuity  was  faced 
with  a  real  test. 


459572 


vi  PREFACE 

The  only  way  of  overcoming  the  airplane  was 
to  build  more  and  better  machines  than  the  en- 
emy possessed.  This  we  tried  to  do,  but  first 
we  had  to  be  taught  by  our  allies  the  latest  re- 
finements of  this  machine,  and  the  war  was  over 
before  we  had  more  than  started  our  aerial  pro- 
gram. The  machine  gun  and  its  accessory, 
barbed  wire  (also  an  American  invention),  were 
overcome  by  the  tank;  and  we  may  find  what 
little  comfort  we  can  in  the  fact  that  its  inven- 
tion was  inspired  by  the  sight  of  an  American 
farm  tractor.  But  the  tank  was  a  British  cre- 
ation and  was  undoubtedly  the  most  important 
invention  of  the  war.  On  the  sea  we  were  faced 
with  a  most  baffling  problem.  The  U-boat  could 
not  be  coped  with  by  the  building  of  swarms  of 
submarines.  The  essential  here  was  a  means 
of  locating  the  enemy  and  destroying  him  even 
while  he  lurked  under  the  surface.  Two  Amer- 
ican inventions,  the  hydrophone  and  the  depth 
bomb,  made  the  lot  of  the  U-boat  decidedly  un- 
enviable and  they  hastened  if  they  did  not  ac- 
tually end  German  frightfulness  on  the  sea. 

But  these  were  by  no  means  the  only  inven- 
tions of  the  war.  Great  Britain  showed  won- 
derful ingenuity  and  resourcefulness  in  many 


PREFACE  vii 

directions;  France  did  marvels  with,  the  air- 
plane and  showed  great  cleverness  in  her  devel- 
opment of  the  tank  and  there  was  a  host  of 
minor  inventions  to  her  credit;  while  Italy 
showed  marked  skill  in  the  creation  of  large  air- 
planes and  small  seacraft. 

The  Central  Powers,  on  the  other  hand,  were 
less  originative  but  showed  marked  resourceful- 
ness in  developing  the  inventions  of  others. 
Forts  were  made  valueless  by  the  large  portable 
Austrian  guns.  The  long  range  gun  that 
shelled  Paris  was  a  sensational  achievement, 
but  it  cannot  be  called  a  great  invention  because 
it  was  of  little  military  value.  The  great  Ger- 
man Zeppelins  were  far  from  a  success  because 
they  depended  for  their  buoyancy  on  a  highly 
inflammable  gas.  It  is  interesting  to  note  that 
while  the  Germans  were  acknowledging  the  fail- 
ure of  their  dirigibles  the  British  were  launch- 
ing an  airship  program,  and  here  in  America 
we  had  found  an  economical  way  of  producing  a 
non-inflammable  balloon  gas  which  promises  a 
great  future  for  aerial  navigation. 

The  most  important  German  contribution  to 
the  war — it  cannot  be  classed  as  an  invention — 
was  poison  gas,  and  it  was  not  long  ere  they  re- 


viil  PREFACE 

gretted  this  infraction  of  -the  rules  of  civilized 
warfare  adopted  at  the  Hague  Conference ;  for 
the  Allies  soon  gave  them  a  big  dose  of  their 
own  medicine  and  before  the  war  was  over, 
fairly  deluged  them  with  lethal  gases  of  every 
variety. 

Many  inventions  of  our  own  and  of  our  allies 
were  not  fully  developed  when  the  war  ended, 
and  there  were  some  which,  although  primarily 
intended  for  purposes  of  war,  will  be  most  serv- 
iceable in  time  of  peace.  For  this  war  was  not 
one  of  mere  destruction.  It  set  men  to  thinking 
as  they  had  never  thought  before.  It  intensi- 
fied their  inventive  faculties,  and  as  a  result,  the 
world  is  richer  in  many  ways.  Lessons  of 
thrift  and  economy  have  been  taught  us.  Man- 
ufacturers have  learned  the  value  of  standardi- 
zation. The  business  man  has  gained  an  appre- 
ciation of  scientific  research. 

The  whole  story  is  too  big  to  be  contained 
within  the  covers  of  a  single  book,  but  I  have 
selected  the  more  important  and  interesting  in- 
ventions and  have  endeavored  to  describe  them 
in  simple  language  for  the  benefit  of  the  reader 
who  is  not  technically  trained. 

A.  EUSSELL  BOND 

New  York,  May,  1919 


CONTENTS 

CHAPTER  PAGE 

I  THE  WAR  IN  AND  UNDER  THE  GROUND    .  3 

II  HAND-GRENADES  AND  TRENCH  MORTARS  .  20 

III  GUNS  THAT  FIRE  THEMSELVES  ....  41 

IV  GUNS  AND  SUPER-GUNS 62 

V  THE  BATTLE  OF  THE  CHEMISTS  ....  85 

VI  TANKS        .     .     .     .     /  .    V    |S  V    .  107 

VII  THE  WAR  IN  THE  AIR  .      .     .,    >  ? .     .  123 

VIII  SHIPS  THAT  SAIL  THE  SKIES      ,     .     ..'•-.  148 

IX  GETTING  THE  RANGE     .     .     .    '•• .     .  .->  169 

X  TALKING  IN  THE  SKY   .     .     .     .     .     .  184 

XI  WARRIORS  OP  THE  PAINT-BRUSH   .     .     .  209 

XII  SUBMARINES    .     .     .     ...     .     .     .  232 

XIII  GETTING  THE  BEST  OP  THE  U-BOAT      .     .  253 

XIV  ' 'DEVIL'S  EGGS "  .     A     .     .     .    -;     .     .  276 
XV    SURFACE  BOATS v     .  298 

XVI    RECLAIMING  THE  VICTIMS  OF  THE  SUBMA- 
RINES    .     .     ,     .     ,     .     .     .     .     .  310 

INDEX  -  339 


LIST  OF  ILLUSTRATIONS 

Oil-tempering  the  lining  of  a  big  gun  .     Frontispiece 

FACING 


PAGE 


Lines  of  zig-zag  trenches  as  viewed  from  an  aero- 

plane  .      .     ......     *     >      .      .      .      .       8 

French  sappers  using  stethoscopes  to  detect  the 

mining  operations  of  the  enemy  ....  9 
A  3-inch  Stokes  mortar  and  two  of  its  shells  .  .  36 
Dropping  a  shell  into  a  6-inch  trench  mortar  .  36 
The  Maxim  machine-gun  operated  by  the  energy 

of  the  recoil  ..........     37 

Colt  machine-gun  partly  broken  away  to  show  the 

operating  mechanism  .  .  .  ,  .  .  .37 
The  Lewis  gun  which  produces  its  own  cooling 

current      ......      .....     44 

The  Benet-Mercie  gun  operated  by  gas  ...  44 
Browning  machine  gun,  weighing  34V2  pounds  .  45 
Browning  machine  rifle,  weight  only  15  pounds  45 
Lewis  machine-guns  in  action  at  the  front  .  .  52 
An  elaborate  German  machine-gun  fort  ...  53 
Comparative  diagram  of  the  path  of  a  projectile 

from  the  German  super-gun  .....  60 
One  of  our  16-inch  coast  defence  guns  on  a  dis- 

appearing mount      ......  61 

Height  of  gun  as  compared  with  the  New  York 

City  Hall       ..........     61 

The  121-mile  gun  designed  by  American  ordnance 

officer  .......   •.*     .....     68 

American  16-inch  rifle  on  a  railway  mount  .  .  69 

xi 


xii  ILLUSTRATIONS 

FACING 
PAGE 

A  long-distance  sub-calibered  French  gun  on  a 

railway  mount 76 

Inside  of  a  shrapnel  shell  and  details  of  the  fuse 

cap 77 

Searchlight  shell  and  one  of  its  candles  ...     77 
Patting  on  the  gas  masks  to  meet  a  gas  cloud  at- 
tack      84 

Even  the  horses  had  to  be  masked 85 

Portable  flame-throwing  apparatus      ....     85 
Liquid  fire  streaming  from  fixed  flame-throwing 

apparatus 92 

Cleaning  up  a  dugout  with  the  "fire-broom"  .     93 
British  tank  climbing  out  of  a  trench  at  Cambrai  112 
Even  trees  were  no  barrier  to  the  British  tank  .   113 
The  German  tank  was  very  heavy  and  cumber- 
some     113 

The  speedy  British  "  Whippet "  tank  that  can 

travel  at  a  speed  of  twelve  miles  per  hour  .  120 
The  French  high-speed  "baby"  tank  ....  120 
Section  through  our  Mark  VIII  tank  showing  the 

layout  of  the  interior 121 

A  Handley-Page  bombing  plane  with  one  of  its 

wings  folded  back 128 

How   an   object   dropped   from   the   Woolworth 

Building  would  increase  its  speed  in  falling  129 
Machine  gun  mounted  to  fire  over  the  blades  of 

the  propeller 136 

Mechanism  for  firing  between  the  blades  of  the 

propeller 136 

It  would  take  a  hundred  horses  to  supply  the 

power  for  a  small  airplane 137 

The   flying-tank 144 

An.  N-C  (Navy-Curtiss)  seaplane  of  the  type  that 

made  the  first  flight  across  the  Atlantic  .      .   145 
A  big  German  Zeppelin  that  was  forced  to  come 
down  on  French  soil   ,  .  148 


ILLUSTRATIONS  xiii 

I-ACING 
PAGE 

Observation  car  lowered  from  a  Zeppelin  sailing 

above  the  clouds 149 

Giant  British  dirigible  built  along  the  lines  of  a 
Zeppelin 156 

One  of  the  engine  cars  or  * '  power  eggs  "  of  a  Brit- 
ish dirigible 156 

Crew  of  the  C-5  (American  coastal  dirigible) 
starting  for  Newfoundland  to  make  a  trans- 
atlantic flight |.  .  .  .  157 

The  curious  tail  of  a  kite  balloon 160 

Observers  in  the  basket  of  an  observation  balloon  160 

Enormous  range-finders  mounted  on  a  gun  turret 

of  an  American  warship 161 

British  anti-aircraft  section  getting  the  range  of 

an  enemy  aviator  ........  176 

A  British  aviator  making  observations  over  the 

German  lines -.,.*»  177 

Radio  headgear  of  an  airman 192 

Carrying  on  conversation  by  radio  with  an  aviator 

miles  away 192 

Long  distance  radio  apparatus  at  the  Arlington 

(Va.)  station 193 

A  giant  gun  concealed  among  trees  behind  the 

French  lines 212 

Observing  the  enemy  from  a  papier-mache  replica 

of  a  dead  horse 213 

Camouflaged  headquarters  of  the  American  26th 

Division  in  France 220 

A  camouflaged  ship  in  the  Hudson  River  on  Vic- 
tory Day 221 

Complex  mass  of  wheels  and  dials  inside  a  German 

submarine 240 

Surrendered  German  submarines,  showing  the  net 

cutters  at  the  bow 241 

Forward  end  of  a  U-boat  ,..,.. 


TIT  ILLUSTRATIONS 


PAGE 


A  depth-bomb  mortar  and  a  set  of  *  *  ash  cans  '  '  at 

the  stern  of  an  American  destroyer  .  .  .  257 
A  depth  bomb  mortar  in  action  and  a  depth  bomb 

snapped  as  it  is  being  hurled  through  the 

air       .      .      .     .      .      .......  260 

Airplane  stunning  a  U-boat  with  a  depth  bomb  .  261 
The  false  hatch  of  a  mystery  ship  .....  268 

The  same  hatch  opened  to  disclose  the  3-inch  gun 

and  crew  ...........   268 

A  French  hydrophone  installation  with  which  the 

presence  of  submarines  was  detected  .  .  269 
Section  of  a  captured  mine-laying  U-boat  .  .  272 
A  paravane  hauled  up  with  a  shark  caught  in  its 

jaws    /    ........     ,.      ...  273 

A  Dutch  mine-sweeper  engaged  in  clearing  the 

North  Sea  of  German  mines  .....  288 
Hooking  up  enemy  anchored  mines  .  .  .  .289 
An  Italian  "sea  tank"  climbing  over  a  harbor 

boom    ............  300 

Deck  of  a  British  aircraft  mothership  or  "hush 

ship"  .........      ...  301 

Electrically  propelled  boat  or  surface  torpedo,  at- 

tacking a  warship   ........  304 

Hauling  a  seaplane  up  on  a  barge  so  that  it  may 

be  towed  ...      ........  305 

Climbing  into  an  armored  diving  suit  ....   320 

Lowering  an  armored  diver  into  the  water  .  .  320 
A  diver's  sea  sled  ready  to  be  towed  along  the 

bed  of  the  sea   .........  321 

The  sea  sled  on  land  showing  the  forward  horizon- 

tal and  after  vertical  rudders  ......   321 

The  diving  sphere  built  for  deep  sea  salvage  op- 

erations   ...........   324 

The  pneumatic  breakwater  .......  325 


INVENTIONS 
OF  THE  GREAT  WAR 


INVENTIONS 
OF  THE  GREAT  WAR 

CHAPTER  I 

THE  WAR  IN  AND  UNDER  THE  GROUND 

FOR  years  the  Germans  had  been  preparing 
for  war.  The  whole  world  knew  this, 
but  it  had  no  idea  how  elaborate  were  their 
preparations,  and  how  these  were  carried  out 
to  the  very  minutest  detail.  When  the  call  to 
arms  was  sounded,  it  was  a  matter  of  only  a 
few  hours  before  a  vast  army  had  been  assem- 
bled— fully  armed,  completely  equipped,  ready 
to  swarm  over  the  frontiers  into  Belgium  and 
thence  into  France.  It  took  much  longer  for 
the  French  to  raise  their  armies  of  defense, 
and  still  longer  for  the  British  to  furnish 
France  with  any  adequate  help.  Despite  the 
heroic  resistance  of  Belgium,  the  Entente  Allies 
were  unprepared  to  stem  the  tide  of  German 


4        INVENTIONS  OF  THE  GREAT  WAR 

soldiers  who  poured  into  the  northern  part  of 
France. 

So  easy  did  the  march  to  Paris  seem,  that  the 
Germans  grew  careless  in  their  advance  and 
then  suddenly  they  met  with  a  reverse  that  sent 
them  back  in  full  retreat.  However,  the  mili- 
tary authorities  of  Germany  had  studied  not 
only  how  to  attack  but  also  how  to  retreat  and 
how  to  stand  on  the  defensive.  In  this,  as  in 
every  other  phase  of  the  conflict,  they  were  far 
in  advance  of  the  rest  of  the  world,  and  after 
their  defeat  in  the  First  Battle  of  the  Marne, 
they  retired  to  a  strong  position  and  hastily 
prepared  to  stand  on  the  defensive.  When 
the  Allies  tried  to  drive  them  farther  back,  they 
found  that  the  German  army  had  simply  sunk 
into  the  ground.  The  war  of  manoeuver  had 
given  way  to  trench  warfare,  which  lasted 
through  long,  tedious  months  nearly  to  the  end 
of  the  great  conflict. 

The  Germans  found  it  necessary  to  make  the 
stand  because  the  Eussians  were  putting  up 
such  a  strong  fight  on  Germany's  eastern  fron- 
tier. Men  had  to  be  withdrawn  from  the  west- 
ern front  to  stem  the  Russian  tide,  which  meant 
that  the  western  armies  of  the  kaiser  had  to 


WAR  IN  AND  UNDER  THE  GROUND       5 

cease  their  offensive  activities  for  the  time  be- 
ing. The  delay  was  fatal  to  the  Germans,  for 
they  had  opposed  to  them  not  only  brave  men 
but  intelligent  men  who  were  quick  to  learn. 
And  when  the  Germans  were  ready  to  resume 
operations  in  the  West,  they  found  that  the 
Allies  also  had  sunk  into  the  ground  and  had 
learned  all  their  tricks  of  trench  warfare,  add- 
ing a  number  of  new  ones  of  their  own. 

The  whole  character  of  the  war  was  changed. 
The  opposing  forces  were  dead-locked  and 
neither  could  break  through  the  other's  lines. 
The  idea  of  digging  into  the  ground  did  not 
originate  with  this  war,  but  never  before  had 
it  been  carried  out  on  so  extensive  a  scale. 
The  inventive  faculties  of  both  sides  were  vainly 
exercised  to  find  some  way  of  breaking  the 
dead-lock.  'Hundreds  of  new  inventions  were 
developed.  The  history  of  war  from  the  days 
of  the  ancient  Eomans  up  to  the  present  time 
was  searched  for  some  means  of  breaking  down 
the  opposing  lines.  However,  the  dead-lock 
was  not  broken  until  a  special  machine  had  been 
invented,  a  traveling  fort.  But  the  story  of 
that  machine  is  told  in  another  chapter. 

At  the  outset  the  Allies  dug  very  shallow 


6         INVENTIONS  OF  THE  GREAT  WAR 

ditches,  such  as  had  been  used  in  previous 
wars.  When  it  was  found  that  these  burrows 
would  have  to  be  occupied  for  weeks  and  months, 
the  French  and  British  imitated  the  Germans 
and  dug  their  trenches  so  deep  that  men  could 
walk  through  them  freely,  without  danger  of  ex- 
posing their  heads  above  ground;  and  as  the 
ditches  grew  deeper,  they  had  to  be  provided 
with  a  firing-step  on  which  the  riflemen  could 
stand  to  fire  over  the  top  of  the  trenches.  The 
trenches  were  zig-zagged  so  that  they  could  not 
be  flanked,  otherwise  they  would  have  made  dan- 
gerous traps  for  the  defenders;  for  had  the 
enemy  gained  one  end  of  the  trench,  he  could 
have  fired  down  the  full  length  of  it,  killing  or 
wounding  every  man  it  contained.  But  zig- 
zagging made  it  necessary  to  capture  each  turn 
separately.  There  were  lines  upon  lines  of 
these  trenches.  Ordinarily  there  were  but 
three  lines,  several  hundred  feet  apart,  with 
communicating  trenches  connecting  them,  and 
then  several  kilometers  l  farther  back  were  re- 
serve trenches,  also  connected  by  communicat- 
ing trenches  with  the  front  lines. 

i  A  kilometer  is,  roughly,  six  tenths  of  a  mile ;  or  six  miles 
•would  equal  ten  kilometers. 


WAR  IN  AND  UNDER  THE  GROUND        7 

Men  did  not  dare  to  show  themselves  out  in 
the  open  near  the  battle-front  for  a  mile  or  more 
behind  the  front-line  trenches,  for  the  enemy 's 
sharp-shooters  were  always  on  the  watch  for  a 
target.  The  men  had  to  stay  in  the  trenches 
day  and  night  for  two  or  more  weeks  at  a  time, 
and  sleeping-accommodations  of  a  very  rough 
sort  were  provided  for  them  in  dugouts  which 
opened  into  the  trenches.  The  dugouts  of  the 
Allies  were  comparatively  crude  affairs,  but  the 
Germans  spent  a  great  deal  of  time  upon  their 
burrows. 

UNDERGROUND  VILLAGES 

When  the  French  first  swept  the  Germans 
back  out  of  their  trenches  along  the  Aisne,  they 
were  astonished  to  find  how  elaborate  were  these 
underground  dwellings.  They  found  that  the 
ground  was  literally  honeycombed  with  rooms 
and  passageways.  Often  the  dugouts  were 
two  stories  in  depth  and  extended  as  much  as 
sixty  feet  below  the  level  of  the  ground.  In 
fact,  all  along  this  part  of  the  front,  the  Ger- 
mans had  a  continuous  underground  village  in 
which  thousands  of  men  were  maintained.  The 
officers'  quarters  were  particularly  well  fitted 


8        INVENTIONS  OF  THE  GREAT  WAR 

up,  and  every  attention  was  given  to  the  com- 
fort of  their  occupants.  There  were  steel 
door-mats  at  the  entrances  of  the  quarters. 
The  walls  were  boarded  and  even  papered. 
The  bedrooms  were  fitted  with  spring  beds, 
i  chiffoniers,  and  wash-stands,  and  all  the  rooms 
were  lighted  with  electric  lamps.  There  were 
spacious  quarters  for  the  men,  with  regular 
underground  mess  halls  and  elaborate  kitchens. 
There  were  power-plants  to  furnish  steam  for 
the  operation  of  pumps  and  for  the  lighting- 
plants  and  for  other  purposes. 

There  was  a  chalk  formation  here  in  which 
were  many  large  natural  caves.  One  enormous 
cave  was  said  to  have  held  thirty  thousand 
soldiers,  and  in  this  section  the  Germans  kept 
large  reserve  forces.  By  digging  far  into  the 
ground,  the  German  troops  secured  protection 
from  shell-fire;  in  fact,  the  horrible  noise  of 
battle  was  heard  only  as  a  murmur,  down  in 
these  depths.  With  characteristic  thorough- 
ness, the  Germans  built  their  trench  system  for 
a  long  stay;  while  the  Allies,  on  the  other  hand, 
looked  upon  their  trenches  as  merely  temporary 
quarters,  which  would  hold  the  enemy  at  bay 
until  they  could  build  up  armies  large  enough 


(C)  Underwood  &  Underwood 

Lines  of  Zig-Zag  Trenches  as  viewed  from  an  Airplane 


Courtesy  of  "Scientific  American  " 

French  Sappers  using  Stethoscopes  to  detect  the 
Mining  Operations  of  the  Enemy 


WAR  IN  AND  UNDER  THE  GROUND        9 

to  drive  the  invaders  out  of  the  country.  The 
construction  of  the  trenches  along  some  parts 
of  the  battle-line  was  particularly  difficult,  be- 
cause of  the  problem  of  drainage.  This  was 
especially  true  in  Flanders,  where  the  trenches 
in  many  cases  were  below  water-level,  and 
elaborate  pumping-systems  had  to  be  installed 
to  keep  them  dry.  Some  of  them  were  concrete- 
lined  to  make  them  waterproof.  In  the  early 
stages  of  the  war,  before  the  trenches  were 
drained,  the  men  had  to  stand  in  water  for  a 
good  part  of  the  time,  and  the  only  way  they 
could  get  -about  at  all  in  the  miry  trenches  was 
by  having  "duck-boards"  in  them.  Duck- 
boards  are  sections  of  wooden  sidewalk  such  as 
we  find  in  small  villages  in  this  country,  con- 
sisting of  a  couple  of  rails  on  which  crosspieces 
of  wood  are  nailed.  These  duck-boards  fairly 
floated  in  the  mud. 

Some  of  the  trenches  were  provided  with 
barbed-wire  barriers  or  gates  calculated  to  halt 
a  raiding-party  if  it  succeeded  in  getting  into 
the  trench.  These  gates  were  swung  up  out 
of  the  way,  but  when  lowered  they  were  kept 
closed  with  a  rather  complicated  system  of  bolts 
which  the  enemy  would  be  unable  to  unfasten 


10       INVENTIONS  OF  THE  GREAT  WAR 

without  some  delay;  and  while  he  was  strug- 
gling to  get  through  the  gate,  he  would  be  a 
target  for  the  bullets  of  -the  defenders. 

HIDING   RAILROADS   IN   DITCHES 

Because  of  the  elaborate  system  of  trenches, 
and  the  distance  from  the  front  line  to  that  part 
of  the  country  where  it  was  safe  to  operate  in 
the  open,  it  was  necessary  to  build  railways 
which  would  travel  through  tunnels  and  com- 
municating trenches  to  the  front  lines.  These 
were  narrow-gage  railroads  and  a  special  stan- 
dard form  of  track  section  was  designed,  which 
was  entirely  of  metal,  something  like  the  track 
sections  of  toy  railroads.  The  tracks  were 
very  quickly  laid  and  taken  up  at  need.  The 
locomotives  had  to  be  silent  and  smokeless  and 
so  a  special  form  of  gasolene  locomotive  was 
invented  to  haul  the  little  cars  along  these  minia- 
ture railroads  to  the  front  lines.  Usually  the 
trench  railroads  did  not  come  to  the  very  front 
of  the  battle-line,  but  their  principal  use  was 
to  carry  shell  to  the  guns  which  were  located 
in  concealed  positions.  Eailroad  or  tramway 
trenches  could  not  be  sharply  zig-zagged  but  had 
to  have  easy  curves,  which  were  apt  to  be  recog- 


WAR  IN  AND  UNDER  THE  GROUND      11 

nized  by  enemy  airplanes,  and  so  they  were 
often  concealed  under  a  covering  of  wire  strewn 
with  leaves. 

PERISCOPES   AND    *  '  SNIPERSCOPES  " 

But  while  the  armies  were  buried  under- 
ground, it  was  necessary  for  them  to  keep  their 
eyes  upon  each  other  so  that  each  might  be 
ready  for  any  sudden  onslaught  of  the  other. 
Snipers  were  always  ready  to  fire  at  any  head 
that  showed  itself  above  the  parapet  of  the 
trench  and  so  the  soldiers  had  to  steal  an  idea 
from  the  submarines  and  build  them  periscopes 
with  which  they  could  look  over  the  top  of  their 
trenches  without  exposing  themselves.  A 
trench  periscope  was  a  very  simple  affair,  con- 
sisting of  a  tube  with  two  mirrors,  one  at  the 
top  and  one  at  the  bottom,  set  at  such  an  angle 
that  a  person  looking  into  the  side  of  the  tube 
at  the  bottom  could  see  out  of  the  opposite  side 
of  the  tube  at  the  top. 

Observation  posts  were  established  wherever 
there  was  a  slight  rise  in  the  ground.  Some- 
times these  posts  were  placed  far  in  advance  of 
the  trenches  and  sometimes  even  behind  the 
trenches  where  it  was  possible  to  obtain  a  good 


12      INVENTIONS  OP  THE  GREAT  WAR 

view  of  the  opposing  lines.  Sometimes  a  tunnel 
would  be  dug  forward,  leading  to  an  outlet 
close  to  the  enemy's  lines,  and  here  an  observer 
would  take  his  position  at  night  to  spy  with  his 
ears  upon  the  activities  of  the  enemy.  Ob- 
servers who  watched  the  enemy  by  day  would 
often  not  dare  to  use  periscopes,  which  might 
be  seen  by  the  enemy  and  draw  a  concentrated 
fire  of  rifles  and  even  shell.  So  that  every 
manner  of  concealment  was  employed  to  make 
the  observation  posts  invisible  and  to  have 
them  blend  with  their  surroundings.  Observ- 
ers even  wore  veils  so  that  the  white  of  their 
skin  would  not  betray  them. 

Snipers  were  equally  ingenious  in  concealing 
themselves.  They  frequently  used  rifles  which 
were  connected  with  a  dummy  butt  and  had 
a  periscope  sighting-attachment.  This  attach- 
ment was  called  a  "sniperscope."  The  rifle- 
barrel  could  be  pushed  through  a  loophole  in 
the  parapet  and  the  sniper  standing  safely  be- 
low the  parapet  could  hold  the  dummy  butt  to 
his  shoulder  and  aim  his  rifle  with  perfect  ac- 
curacy by  means  of  the  periscope.  It  was  next 
to  impossible  to  locate  a  sniper  hidden  in  this 
way.  One  method  of  doing  it  was  to  examine 


WAR  IN  AND  UNDER  THE  GROUND   13 

rubbish,  tin  cans,  or  any  object  that  had  been 
penetrated  by  a  bullet  and  note  the  direction 
taken  by  the  bullet.  This  would  give  a  line 
leading  toward  the  source  of  the  shot,  and 
when  a  number  of  such  lines  were  traced,  they 


Redrawn  from  Military  Map  Reading  by  permission  of  E.  0.  McKay 
FIG.  1.     A  "sniperscope"  with  which  a  sharpshooter  could  take 
aim  without  showing  his  head  above  the  parapet 

would  cross  at  a  spot  where  the  sniper  or 
his  gun  wras  stationed,  and  a  few  shell  would 
put  the  man  out  of  business.  Dummy  heads 
of  papier  mache  were  sometimes  stuck  above 
the  parapet  to  draw  the  fire  of  enemy  snip- 
ers and  the  ^bullet-holes  which  quickly  ap- 


14       INVENTIONS  OF  THE  GREAT  WAR 

peared  in  them  were  studied  to  discover  the  lo- 
cation of  the  snipers. 

Sometimes  fixed  rifles  were  used.  These 
were  set  on  stands  so  that  'they  could  be  very 
accurately  trained  upon  some  important  enemy 


Redrawn  from  Military  Map  Reading  by  permission  of  E.  C.  McKay 
FIG.  2.     A  fixed  rifle  stand  arranged  to  be  fired  after  dark 

post.  Then  they  could  be  fired  in  the  dark, 
without  aiming,  to  disturb  night  operations  of 
the  enemy.  Often  a  brace  of  rifles,  as  many  as 
six,  would  be  coupled  up  to  be  fired  simultane- 
ously, and  by  operating  a  single  lever  each  gun 
would  throw  out  the  empty  cartridge  shell  and 
bring  a  fresh  one  into  position. 


WAR  IN  AND  UNDER  THE  GROUND  15 

STEEL   BRIER   PATCHES 

The  most  important  defense  of  a  trench  sys- 
tem consisted  in  the  barbed-wire  entanglements 
placed  before  it.  Barbed  wire,  by  the  way,  is 
an  American  invention,  but  it  was  originally 
intended  for  the  very  peaceful  purpose  for  keep- 
ing cattle  within  bounds.  Long  ago  it  was  used 
in  war,  but  never  to  the  extent  to  which  it  was 
employed  in  this  world  struggle.  The  entangle- 
ments were  usually  set  up  at  night  and  were 
merely  fences  consisting  of  stout  posts  driven 
into  the  ground  and  strung  with  barbed  wire 
running  in  all  directions,  so  as  to  make  an  im- 
penetrable tangle.  Where  it  wras  possible  to 
prepare  the  entanglements  without  disturbance 
and  the  position  was  an  important  one,  the  mass 
of  barbed  wire  often  extended  for  a  hundred 
yards  or  more  in  depth.  Just  beyond  the  en- 
tanglements trip-wires  were  sometimes  used. 
A  trip-wire  was  a  slack  wire  which  was  laid  on 
the  ground.  Before  being  laid,  the  wire  was 
tightly  coiled  so  that  it  would  not  lie  flat,  but 
would  catch  the  feet  of  raiders  and  trip  them  up. 
Each  side  had  "gates"  in  the  line  through 
which  this  wire  could  quickly  be  removed  to 


16       INVENTIONS  OF  THE  GREAT  WAR 

let  its  own  raiding-parties  through.  Some- 
times raiders  used  tunnels,  with  outlets  be- 
yond the  barbed  wire,  but  they  had  to  cut  their 
way  through  the  metal  brier  patches  of  their 
opponents. 

Early  in  the  war,  various  schemes  were  de- 
vised for  destroying  the  entanglements.  There 
were  bombs  in  the  form  of  a  rod  about  twelve 
feet  long,  which  could  be  pushed  under  the  wire 
and  upon  exploding  would  tear  it  apart.  An- 
other scheme  was  to  fire  a  projectile  formed 
like  a  grapnel.  The  projectile  was  attached 
to  the  end  of  a  cable  and  was  fired  from  a 
small  gun  in  the  same  way  that  life-lines  are 
thrown  out  to  wrecks  near  shore.  Then  the 
cable  would  be  wound  up  on  a  winch  and  the 
grapnel  hooks  would  tear  the  wire  from  its  fast- 
enings. Such  schemes,  however,  did  not  prove 
very  practicable,  and  it  was  eventually  found 
that  a  much  better  way  of  destroying  barbed 
wire  was  to  bombard  it  with  high-explosive 
shell,  which  would  literally  blow  the  wire  apart. 
But  it  required  a  great  deal  of  shelling  to  de- 
stroy these  entanglements,  and  it  was  really 
not  until  the  tank  was  invented  that  such  ob- 
structions could  be  flattened  out  so  that  they 


WAR  IN  AND  UNDER  THE  GROUND   17 

formed  no  bar  to  the  passage  of  the  soldiers. 
The  Germans  not  only  used  fixed  entangle- 
ments, but  they  had  large  standard  sections 
of  barbed  wire  arranged  in  the  form  of  big 
cylindrical  frames  which  would  be  carried 
easily  by  a  couple  of  men  and  could  be  placed 
in  position  at  a  moment's  notice  to  close  a  gap 
in  the  line  or  even  to  build  up  new  lines  of  wire 
obstruction. 

MINES   AND   COUNTEB-MINES 

In  the  earlier  stages  of  the  war  it  proved  so 
impossible  to  capture  a  trench  when  it  was  well 
defended  by  machine-guns  that  efforts  were 
made  to  blow  up  the  enemy  by  means  of  mines. 
Tunnels  were  dug  reaching  out  under  the 
enemy's  lines,  and  large  quantities  of  explo- 
sives were  stored  in  them.  At  the  moment  when 
it  was  intended  to  make  an  assault,  there  would 
be  a  heavy  cannonading  to  disconcert  the  enemy, 
and  then  the  mine  would  be  touched  off.  In 
the  demoralizing  confusion  that  resulted,  the 
storming-party  would  sweep  over  the  enemy. 
Such  mines  were  tried  on  both  sides,  and  the 
only  protection  against  them  was  to  out-guess 
the  other  side  and  build  counter-mines. 


18      INVENTIONS  OF  THE  GREAT  WAR 

If  it  were  suspected,  from  the  importance  of 
a  certain  position  and  the  nature  of  the  ground, 
that  the  enemy  would  probably  try  to  under- 
mine it,  the  defenders  would  dig  tunnels  of  their 
own  toward  the  enemy  at  a  safe  distance  be- 
yond their  own  lines  and  establish  listeners 
there  to  see  if  they  could  hear  the  mining- 
operations  of  their  opponents.  Very  delicate 
microphones  were  used,  which  the  listeners 
would  place  on  the  ground  or  against  the  walls 
of  their  tunnel.  Then  they  would  listen  for  the 
faintest  sound  of  digging,  just  as  a  doctor 
listens  through  a  stethoscope  to  the  beating 
of  a  patient's  heart  or  the  rush  of  air  through 
his  lungs.  When  these  listening-instruments 
picked  up  the  noise  of  digging,  the  general  di- 
rection of  the  digging  could  be  followed  out  by 
placing  the  instrument  at  different  positions 
and  noting  where  the  noise  was  loudest.  Then 
a  counter-mine  would  be  extended  in  that  direc- 
tion, far  enough  down  to  pass  under  the  enemy's 
tunnel,  and  at  the  right  moment,  a  charge  of 
TNT  (trinitrotoluol)  would  be  exploded,  which 
would  destroy  the  enemy's  sappers  and  put  an 
end  to  their  ambitious  plans. 

A  very  interesting  case  of  mining  was  fur- 


WAR  IN  AND  UNDER  THE  GROUND      19 

nished  by  the  British  when  they  blew  up  the  im- 
portant post  of  Messines  Eidge.  This  was 
strongly  held  by  the  Germans  and  the  only  way 
of  dislodging  the  enemy  was  to  blow  off  the  top 
of  the  ridge.  Before  work  was  started,  geolo- 
gists were  called  upon  to  determine  whether 
or  not  the  ground  were  suitable  for  mining- 
operations.  They  picked  out  a  spot  where  the 
digging  was  good  from  the  British  side,  but 
where,  if  counter-mines  were  attempted  from 
the  German  side,  quicksands  would  be  encount- 
ered and  tunneling  of  any  sort  would  be  diffi- 
cult. The  British  sappers  could,  therefore,  pro- 
ceed with  comparative  safety.  The  Germans 
suspected  that  something  of  the  sort  was  being 
undertaken,  but  they  found  it  very  difficult  to 
dig  counter-mines.  However,  one  day  their 
suspicions  were  confirmed,  when  the  whole  top 
of  the  hill  was  blown  off,  with  a  big  loss  of 
German  lives.  In  the  assault  that  followed  the 
British  captured  the  position  and  it  was  an- 
nexed to  the  British  lines. 


CHAPTER  II 

HAND-GRENADES  AND  TRENCH  MORTARS 

IN  primitive  times  battles  were  fought  hand- 
to-hand.  The  first  implements  of  war  were 
clubs  and  spears  and  battle-axes,  all  intended 
for  fighting  at  close  quarters.  The  bow  and  ar- 
row enabled  men  to  fight  at  a  distance,  but 
shields  and  armor  were  so  effective  a  defense 
that  it  was  only  by  hand-to-hand  fighting  that  a 
brave  enemy  could  be  defeated.  Even  the  in- 
vention of  gunpowder  did  not  separate  the  com- 
batants permanently,  for  although  it  was  possi- 
ble to  hurl  missiles  at  a  great  distance,  cannon 
were  so  slow  in  their  action  that  the  enemy  could 
rush  them  between  shots.  Shoulder  firearms 
also  were  comparatively  slow  in  the  early  days, 
and  liable  to  miss  fire,  and  it  was  not  until  the 
automatic  rifle  of  recent  years  was  fully  de- 
veloped that  soldiers  learned  to  keep  their  dis- 
tance. 

When  the  great  European  war  started,  mili- 
tary authorities  had  come  to  look  upon  war  at 

20 


HAND-GRENADES  21 

close  quarters  as  something  relegated  to  by- 
gone days.  Even  the  bayonet  was  beginning 
to  be  thought  of  little,  use.  Rifles  could  be 
charged  and  fired  so  rapidly  and  machine-guns 
could  play  such  a  rapid  tattoo  of  bullets,  that 
it  seemed  impossible  for  men  to  come  near 
enough  for  hand-to-hand  fighting,  except  at  a 
fearful  cost  of  life.  In  developing  the  rifle, 
every  effort  was  made  to  increase  its  range  so 
that  it  could  be  used  with  accuracy  at  a  distance 
of  a  thousand  yards  and  more.  But  when  the 
Germans,  after  their  retreat  in  the  First  Battle 
of  the  Marne,  dug  themselves  in  behind  the 
Aisne,  and  the  French  and  British  too  found  it 
necessary  to  seek  shelter  from  machine-gun  and 
rifle  fire  by  burrowing  into  the  ground,  it  be- 
came apparent  that  while  rifles  and  machine- 
guns  could  drive  the  fighting  into  the  ground, 
they  were  of  little  value  in  continuing  the  fight 
after  the  opposing  sides  had  buried  themselves. 
The  trenches  were  carried  close  to  one  another, 
in  some  instances  being  so  close  that  the 
soldiers  could  actually  hear  the  conversation  of 
their  opponents  across  the  intervening  gap.  Un- 
der such  conditions  long-distance  firearms  were 
of  very  little  practical  value.  What  was  needed 


22      INVENTIONS  OF  THE  GREAT  WAR 

was  a  short-distance  gun  which  would  get  down 
into  the  enemy  trenches.  To  be  sure,  the 
trenches  could  be  shelled,  but  the  shelling  had  to 
be  conducted  from  a  considerable  distance, 
where  the  artillery  would  be  immune  to  attack, 
and  it  was  impossible  to  give  a  trench  the  par- 
ticular and  individual  attention  which  it  would 
receive  at  the  hands  of  men  attacking  it  at 
close  quarters. 

Before  we  go  any  farther  we  must  learn  the 
meaning  of  the  word  "trajectory."  No  bullet 
or  shell  travels  in  a  straight  line.  As  soon  as 
it  leaves  the  muzzle  of  the  gun,  it  begins  to  fall, 
and  its  course  through  the  air  is  a  vertical 
curve  that  brings  it  eventually  down  to  the 
ground.  This  curve  is  called  the  "trajectory." 
No  gun  is  pointed  directly  at  a  target,  but  above 
it,  so  as  to  allow  for  the  pull  of  gravity.  The 
faster  the  bullet  travels,  the  flatter  is  this  curve 
or  trajectory,  because  there  is  less  time  for  it 
to  fall  before  it  reaches  its  target.  Modern 
rifles  fire  their  missiles  at  so  high  a  speed  that 
the  bullets  have  a  very  flat  trajectory.  But  in 
trench  warfare  a  flat  trajectory  was  not  de- 
sired. What  was  the  use  of  a  missile  that  trav- 
eled in  a  nearly  straight  line,  when  the  object  to 


HAND-GRENADES  23 

be  hit  was  hiding  in  the  ground?  Trench  fight- 
ing called  for  a  missile  that  had  a  very  high  tra- 
jectory, so  that  it  would  drop  right  into  the 
enemy  trench. 

HAND-ABTILLERY 

Trench  warfare  is  really  a  close-quarters 
fight  of  fort  against  fort,  and  the  soldiers  who 
manned  the  forts  had  to  revert  to  the  ancient 
methods  of  fighting  an  enemy  intrenched  be- 
hind fortifications.  Centuries  ago,  not  long 
after  the  first  use  of  gunpowder  in  war,  small 
explosive  missiles  were  invented  which  could  be 
thrown  by  hand.  These  were  originally  known 
as  "flying  mortars/'  The  missile  was  about 
the  size  of  an  orange  or  a  pomegranate,  and  it 
was  filled  with  powder  and  slugs.  A  small  fuse, 
which  was  ignited  just  before  the  device  was 
thrown,  was  timed  to  explode  the  missile  when 
it  reached  the  enemy.  Because  of  its  size  and 
shape,  and  because  the  slugs  it  contained  corre- 
sponded, in  a  manner,  to  the  pulp-covered  seeds 
with  which  a  pomegranate  is  filled,  the  missile 
was  called  a  " grenade.'7 

Grenades  had  fallen  out  of  use  in  modern  war- 
fare, although  they  had  been  revived  to  a  small 


24      INVENTIONS  OF  THE  GREAT  WAR 

extent  in  the  Eusso-Japanese  war,  and  had  been 
used  with  some  success  by  the  Bulgarians  and 
the  Turks  in  the  Balkan  wars.  And  yet  they 
had  not  been  taken  very  seriously  by  the  mili- 
tary powers  of  Europe,  except  Germany.  Ger- 
many was  always  on  the  lookout  for  any  device 
that  might  prove  useful  in  war,  and  when  the 
Germans  dug  themselves  in  after  the  First  Bat- 
tle of  the  Marne,  they  had  large  quantities  of 
hand-grenades  for  their  men  to  toss  over  into 
the  trenches  of  the  Allies.  These  missiles 
proved  very  destructive  indeed.  They  took  the 
place  of  artillery,  and  were  virtually  hand- 
thrown  shrapnel. 

The  French  and  British  were  entirely  unpre- 
pared for  this  kind  of  fighting,  and  they  had 
hastily  to  improvise  offensive  and  defensive 
weapons  for  trench  warfare.  Their  hand- 
grenades  were  at  first  merely  tin  cans  filled 
with  bits  of  iron  and  a  high  explosive  in  which 
a  fuse-cord  was  inserted.  The  cord  was  lighted 
by  means  of  a  cigarette  and  then  the  can  with 
its  spluttering  fuse  was  thrown  into  the  enemy 
lines.  As  time  went  on  and  the  art  of  grenade 
fighting  was  learned,  the  first  crude  missiles 
were  greatly  improved  upon  and  grenades  were 


HAND-GRENADES  25 

made    in    many    forms    for    special    service. 

There  was  a  difference  between  grenades 
hurled  from  sheltered  positions  and  those  used 
in  open  fighting.  When  the  throwers  were 
sheltered  behind  their  own  breastworks,  it  mat- 
tered not  how  powerful  was  the  explosion  of  the 
grenade.  We  must  remember  that  in  "  hand- 
artillery  "  the  shell  is  far  more  powerful  in  pro- 
portion to  the  distance  it  is  thrown  than  the 
shell  fired  from  a  gun,  and  many  grenades  were 
so  heavily  charged  with  explosives  that  they 
would  scatter  death  and  destruction  farther 
than  they  could  be  thrown  by  hand.  The  grena- 
dier who  cast  one  of  these  grenades  had  to 
duck  under  cover  or  hide  under  the  walls  of 
his  trench,  else  the  fragments  scattered  by  the 
exploding  missile  might  fly  back  and  injure  him. 
Some  grenades  would  spread  destruction  to  a 
distance  of  over  three  hundred  feet  from  the 
point  of  explosion.  For  close  work,  grenades 
of  smaller  radius  were  used.  These  were  em- 
ployed to  fight  off  a  raiding-party  after  it  had 
invaded  a  trench,  and  the  destructive  range  of 
these  grenades  was  usually  about  twenty-five 
feet. 

Hand-grenades  came  to  be  used  in  all  the 


26       INVENTIONS  OF  THE  GREAT  WAR 

different  ways  that  artillery  was  used.  There 
were  grenades  which  were  filled  with  gas,  not 
only  of  the  suffocating  and  tear-producing 
types,  but  also  of  the  deadly  poisonous  variety. 
There  were  incendiary  grenades  which  would 
set  fire  to  enemy  stores,  and  smoke  grenades 
which  would  produce  a  dense  black  screen  be- 
hind which  operations  could  be  concealed  from 
the  enemy.  Grenades  were  used  in  the  same 
way  that  shrapnel  was  used  to  produce  a  bar- 
rage or  curtain  of  fire,  through  which  the  enemy 
could  not  pass  without  facing  almost  certain 
death.  Curtains  of  fire  were  used  not  only  for 
defensive  purposes  when  the  enemy  was  attack- 
ing, but  also  to  cut  off  a  part  of  the  enemy  so 
that  it  could  not  receive  assistance  and  would 
be  obliged  to  surrender.  In  attacks  upon  the 
enemy  lines,  grenades  were  used  to  throw  a 
barrage  in  advance  of  the  attacking  soldiers  so 
as  to  sweep  the  ground  ahead  clear  of  the 
enemy. 

The  French  paid  particular  attention  to  the 
training  of  grenadiers.  A  man  had  to  be  a 
good,  cool-headed  pitcher  before  he  could  be 
classed  as  a  grenadier.  He  must  be  able  to 
throw  his  grenade  with  perfect  accuracy  up  to 


HAND-GRENADES  27 

a  distance  of  seventy  yards,  and  to  maintain  an 
effective  barrage.  The  grenadier  carried  his 
grenades  in  large  pockets  attached  -to  his  belt, 
and  he  was  attended  by  a  carrier  who  brought 
up  grenades  to  him  in  baskets,  so  that  he  was 
served  with  a  continuous  supply. 

LONG-DISTANCE    GRENADE-THROWING 

All  this  relates  to  short-distance  fighting,  but 
grenades  were  also  used  for  ranges  beyond  the 
reach  of  the  pitcher's  arm.  Even  back  in  the 
sixteenth  century,  the  range  of  the  human  arm 
was  not  great  enough  to  satisfy  the  combatants 
and  grenadiers  used  a  throwing-implement, 
something  like  a  shovel,  with  which  the  grenade 
was  slung  to  a  greater  distance,  in  much  the 
same  way  as  a  lacrosse  ball  is  thrown.  Later, 
grenades  were  fitted  with  light,  flexible  wooden 
handles  and  were  thrown,  handle  and  all,  at  the 
enemy.  By  this  means  they  could  be  slung  to 
a  considerable  distance.  Such  grenades  were 
used  in  the  recent  war,  particularly  by  the  Ger- 
mans. The  handle  was  provided  with  streamers 
so  as  to  keep  the  grenade  head-on  to  the  enemy, 
and  it  was  usually  exploded  by  percussion  on 
striking  its  target.  These  long-handled  gre- 


28       INVENTIONS  OF  THE  GREAT  WAR 

nades,  however,  were  clumsy 
and  bulky,  and  the  grenadier  re- 
quired a  good  deal  of  elbow- 
room  when  throwing  them. 

A  much  better  plan  was  to 
hurl  them  with  the  aid  of  a  gun. 
A  rifle  made  an  excellent  short- 
distance  mortar.  With  it  gre- 
nades could  be  thrown  from 
three  to  four  hundred  yards. 
The  grenade  was  fastened  on  a 
rod  which  was  inserted  in  the 
barrel  of  the  rifle  and  then  it  was 
fired  out  of  the  gun  by  the  ex- 
plosion of  a  blank  cartridge. 
The  butt  of  the  rifle  was  rested 
on  the  ground  and  the  rifle  was 
tilted  so  as  to  throw  the  grenade 
up  into  the  air  in  the  way  that 
a  mortar  projects  its  shell. 


FIG.  3. 


STRIKING   A   LIGHT 

The  lighting  of  the  grenade 
fuses  with  a  cigarette  did  very 
A  rifle  grenade      wen  for  the  early  tin-can  gre- 

fitted      to      the 

muzzle  of  a  rifle      nades,  but  the  cigarettes  were 


HAND-GRENADES  29 

not  always  handy,  particularly  in  the  heat 
of  battle,  and  something  better  had  to  be  de- 
vised. One  scheme  was  to  use  a  safety- 
match  composition  on  the  end  of  a  fuse.  This 
was  covered  with  waxed  paper  to  protect 
it  from  the  weather.  The  grenadier  wore 
an  armlet  covered  with  a  friction  compo- 
sition such  as  is  used  on  a  safety-match  box. 
Before  the  grenade  was  thrown,  the  waxed 
paper  was  stripped  off  and  the  fuse  was  lighted 
by  being  scratched  on  the  armlet.  In  another 
type  the  fuse  was  lighted  by  the  twisting  of  a 
cap  which  scratched  a  match  composition  on  a 
friction  surface.  A  safety-pin  kept  the  cap 
from  turning  until  the  grenadier  was  ready  to 
throw  the  grenade. 

The  Mills  hand-grenade,  which  proved  to  be 
the  most  popular  type  used  by  the  British  Army, 
was  provided  with  a  lever  which  was  normally 
strapped  down  and  held  by  means  of  a  safety- 
pin.  Fig.  4  shows  a  sectional  view  of  this 
grenade.  Just  before  the  missile  was  thrown, 
it  was  seized  in  the  hand  so  that  the  lever  was 
held  down.  Then  the  safety-pin  was  removed 
and  when  the  grenade  was  thrown,  the  lever 
would  spring  up  under  pull  of  the  spring  A. 


30       INVENTIONS  OF  THE  GREAT  WAR 

This  would  cause  the  pin  B  to  strike  the  per- 
cussion cap  C,  which  would  light  the  fuse  D. 
The  burning  fuse  would  eventually  carry  the  fire 
to  the  detonator  E,  which  would  touch  off  the 
main  explosive,  shattering  the  shell  of  the  gre- 
nade and  scattering  its  fragments  in  all  direc- 


Fia.  4.     Details  of  the  Mills  hand  grenade 

tions.  The  shell  of  the  grenade  was  indented 
so  that  it  would  break  easily  into  a  great  many 
small  pieces. 

There  were  some  advantages  in  using  gre- 
nades lighted  by  fuse  instead  of  percussion, 
and  also  there  were  many  disadvantages.  If 
too  long  a  time-fuse  were  used,  the  enemy  might 


HAND-GRENADES 


31 


catch  the  grenade,  as  you  would  a  baseball  and 
hurl  it  back  before  it  exploded.  This  was  a 
hazardous  game,  but  it  was  often  done. 

Among  the  different 
types  of  grenades  which 
the  Germans  used  was 
one  provided  with  a  par- 
achute as  shown  in  Fig. 
5.  The  object  of  the  par- 
achute was  to  keep  the 
head  of  the  grenade  to- 
ward the  enemy,  so  that 
when  it  exploded  it  would 
expend  its  energies  for- 
ward and  would  not  cast 
fragments  back  toward 
the  man  who  had  thrown 
it.  This  was  a  very  sen- 
sitive grenade,  arranged 
to  be  fired  by  percussion, 
but  it  was  so  easily  ex- 
ploded that  the  firing- 
mechanism  was  not  re- 
leased until  after  the 
grenade  had  been  thrown. 
In  the  handle  of  this  gre- 


SAFETY  CORD 


FIG.  5.     A  German  para- 
chute grenade 


32      INVENTIONS  OF  THE  GREAT  WAR 

nade  there  was  a  bit  of  cord  about  twenty  feet 
long.  One  end  of  this  was  attached  to  a  safety- 
needle,  A,  while  the  other  end,  formed  into  a 
loop,  was  held  by  the  grenadier  when  he  threw 
the  grenade.  Not  until  the  missile  had  reached 
a  height  of  twelve  or  thirteen  feet  would  the 
pull  of  the  string  withdraw  the  needle  A.  This 
would  permit  a  safety-hook,  B,  to  drop  out  of 
a  ring,  C,  on  the  end  of  a  striker  pellet,  D. 
When  the  grenade  struck,  the  pellet  D  would 
move  forward  and  a  pin,  E,  would  strike  a  cap 
on  the  detonator  F,  exploding  the  missile.  This 
form  of  safety-device  was  used  on  a  number  of 
German  grenades. 

The  British  had  another  scheme  for  locking 
the  mechanism  until  after  the  grenade  had 
traveled  some  distance  through  the  air.  De- 
tails of  this  grenade,  which  was  of  the  type 
adopted  to  be  fired  from  a  rifle,  are  shown  in 
Fig.  6.  The  striker  A  is  retained  by  a  couple 
of  bolts,  B,  which  in  turn  are  held  in  place  by 
a  sleeve,  C.  On  the  sleeve  is  a  set  of  wind- 
vanes,  D.  As  the  grenade  travels  through  the 
air,  the  wind-vanes  cause  the  sleeve  C  to  re- 
volve, screwing  it  down  clear  of  the  bolts  B, 
which  then  drop  out,  permitting  the  pin  A  to 


uiiiiiiiii/imii 


FIG.  6.  British  riile  grenade  with  a  safety-device  which  is 
unlocked  by  the  rush  of  air  against  a  set  of  inclined  vanes, 
D,  when  the  missile  is  in  flight 


33 


34       INVENTIONS  OF  THE  GREAT  WAR 

strike  the  detonator  E  upon  impact  of  the  gre- 
nade with  its  target. 
The  Germans  had  one  peculiar  type  which 


FIG.  7.     Front,    side,    and    sectional    views    of    a    disk-shaped 
German  grenade 

was  in  the  shape  of  a  disk.  In  the  disk  were 
six  tubes,  four  of  which  carried  percussion  caps 
so  that  the  grenade  was  sure  to  explode  no  mat- 
ter on  which  tube  it  fell.  The  disk  was  thrown 


FlQ.  8.     A  curious  German  hand  grenade  shaped  like  a  hair 

brush 

with  the  edge  up,  and  it  would  roll  through  the 
air.  Another  type  of  grenade  was  known  as 
the  hair-brush  grenade  because  it  had  a  rectan- 


HAND-GRENADES  35 

gular  body  of  tin  about  six  inches  long  and  two 
and  three  quarter  inches  wide  and  deep,  which 
was  nailed  to  a  wooden  handle. 

MINIATURE   ARTILLERY 

Hand-artillery  was  very  effective  as  far  as 
it  went,  but  it  had  its  limitations.  Grenades 
could  not  be  made  heavier  than  two  pounds  in 
weight  if  they  were  to  be  thrown  by  hand;  in 
fact,  most  of  them  were  much  lighter  than  that. 
If  they  were  fired  from  a  rifle,  the  range  was 
increased  but  the  missile  could  not  be  made  very 
much  heavier.  TNT  is  a  very  powerful  ex- 
plosive, but  there  is  not  room  for  much  of  it 
in  a  grenade  the  size  of  a  large  lemon.  Trench 
fighting  was  a  duel  between  forts,  and  while  the 
hand-artillery  provided  a  means  of  attacking 
the  defenders  of  a  fort,  it  made  no  impression  on 
the  walls  of  the  fort.  It  corresponded  to  shrap- 
nel fire  on  a  miniature  scale,  and  something 
corresponding  to  high-explosive  fire  on  a  small 
scale  was  necessary  if  the  opposing  fortifica- 
tions were  to  be  destroyed.  To  meet  this  prob- 
lem, men  cast  their  thoughts  back  to  the  primi- 
tive artillery  of  the  Eomans,  who  used  to  hurl 
great  rocks  at  the  enemy  with  catapults.  And 


36      INVENTIONS  OF  THE  GREAT  WAR 

the  trench  fighters  actually  rigged  up  catapults 
with  which  they  hurled  heavy  bombs  at  the 
enemy  lines.  All  sorts  of  ingenious  catapults 
were  built,  some  modeled  after  the  old  Roman 
machines.  In  some  of  these  stout  timbers  were 
used  as  springs,  in  others  there  were  powerful 
coil  springs.  It  was  not  necessary  to  cast  the 
bombs  far.  For  distant  work  the  regular  ar- 
tillery could  be  used.  What  was  needed  was  a 
short-distance  gun  for  heavy  missiles  and  that 
is  what  the  catapult  was. 

But  the  work  of  the  catapult  was  not  really 
satisfactory.  The  machine  was  clumsy ;  it  occu- 
pied too  much  space,  and  it  could  not  be  aimed 
very  accurately.  It  soon  gave  way  to  a  more 
modern  apparatus,  fashioned  after  the  old 
smooth-bore  mortars.  This  was  a  miniature 
mortar,  short  and  wide-mouthed.  A  rifled  bar- 
rel was  not  required,  because,  since  the  missile 
was  not  to  be  hurled  far,  it  was  not  necessary  to 
set  it  spinning  by  means  of  rifling  so  as  to  hold 
it  head-on  to  the  wind. 

GIANT   PEA-SHOOTEBS 

Better  aim  was  secured  when  a  longer-bar- 
reled trench  mortar  came  to  be  used.  In  the 


Press  Illustrating  Service 

A  3-inch  Stokes  mortar  and  two  of  its  shells 


Press  Illustrating  Service 

Dropping  a  shell  into  a  6-inch  trench  mortar 


1    J 


is-s 


U 


HAND-GRENADES  37 

trench,  weight  was  an  important  item.  There 
was  no  room  in  which  to  handle  heavy  guns,  and 
the  mortar  had  to  be  portable  so  that  it  could 
be  carried  forward  by  the  infantry  in  a  charge. 
As  the  walls  of  a  light  barrel  might  be  burst 
by  the  shock  of  exploding  powder,  compressed 
air  was  used  instead.  The  shell  was  virtually 
blown  out  of  the  gun  in  the  same  way  that  a  boy 
blows  missiles  out  of  a  pea-shooter.  That  the 
shell  might  be  kept  from  tumbling,  it  was  fitted 
with  vanes  at  the  rear.  These  acted  like  the 
feathers  of  an  arrow  to  hold  the  missile  head-on 
to  its  course. 

The  French  in  particular  used  this  type  of 
mortar  and  the  air-pump  was  used  to  compress 
the  air  that  propelled  the  shell  or  aerial  torpedo, 
or  else  the  propelling  charge  was  taken  from 
a  compressed-air  tank.  Carbon-dioxide,  the 
gas  used  in  soda  water,  is  commonly  stored  in 
tanks  under  high  pressure  and  this  gas  was 
sometimes  used  in  place  of  compressed  air. 
When  the  gas  in  the  tank  was  exhausted  the  lat- 
ter could  be  recharged  with  air  by  using  a  hand- 
pump.  Two  or  three  hundred  strokes  of  the 
pump  would  give  a  pressure  of  one  hundred  and 
twenty  to  one  hundred  and  fifty  pounds  per  inch, 


38       INVENTIONS  OF  THE  GREAT  WAK 

and  would  supply  enough  air  to  discharge  a 
number  of  shell.  The  air  was  let  into  the  bar- 
rel of  the  mortar  in  a  single  puff  sufficient  to 
launch  the  shell;  then  the  tank  was  cut  off  at 
once,  so  that  the  air  it  contained  would  not 
escape  and  go  to  waste. 

THE   STOKES   MORTAR 

However,  the  most  useful  trench  mortar  de- 
veloped during  the  war  was  invented  by  Wilfred 
Stokes,  a  British  inventor.  In  this  a  compara- 
tively slow-acting  powder  was  used  to  propel 
the  missile,  and  so  a  thin-walled  barrel  could 
be  used.  The  light  Stokes  mortar  can  easily 
be  carried  over  the  shoulder  by  one  man.  It 
has  two  legs  and  the  barrel  itself  serves  as 
a  third  leg,  and  the  mortar  stands  like  a  tripod. 
The  two  legs  are  adjustable,  so  that  the  barrel 
can  be  inclined  to  any  desired  angle.  It  took 
but  a  moment  to  set  up  the  mortar  for  action  in 
a  trench  or  shell-hole. 

Curiously  enough,  there  is  no  breech-block, 
trigger  or  fire-hole  in  this  mortar.  It  is  fired 
merely  by  the  dropping  of  the  missile  into  the 
mouth  of  the  barrel.  The  shell  carries  its  own 
propelling  charge,  as  shown  in  Fig.  9.  This 


HAND-GRENADES  39 

is  in  the  form  of  rings,  A,  which  are  fitted  on 
a  stem,  B.  At  the  end  of  the  stem  are  a  de- 
tonating cap  and  a  cartridge,  to  ignite  the 
propellant,  A.  At  the  bottom  of  the  mortar 
barrel,  there  is  a  steel  point,  E,  known  as  the 


FIG.  9.     Sectional  view  of  a  3-inch  Stokes  mortar  showing  a 
shell  at  the  instant  of  striking  the  anvil 


"anvil."  When  the  shell  is  dropped  into  the 
mortar,  the  cap  strikes  the  anvil,  exploding  the 
cartridge  and  touching  off  the  propelling 
charge,  A.  The  gases  formed  by  the  burning 
charge  hurl  the  shell  out  of  the  barrel  to  a 
distance  of  several  hundred  yards. 


40      INVENTIONS  OF  THE  GREAT  WAR 


The  first  Stokes  mortar  was  made  to  fire  a 
3-inch  shell,  but  the  mortar  grew  in  size  until 

it  could  hurl  shell  of  6- 
inch  and  even  8y2-mch 
size.  Of  course,  the 
larger  mortars  had  to 
have  a  very  substantial 
base.  They  were  not  so 
readily  portable  as  the 
smaller  ones  and  they 
could  not  be  carried  by 
one  man;  but  compared 
with  ordinary  artillery  of 
the  same  bore  they  were 
immeasurably  lighter 
and  could  be  brought  to 
advanced  positions  and 
set  up  in  a  very  short 
6-inch  trench  time.  The  larger  shell 
have  tail-vanes,  as  shown 
in  Fig.  10,  to  keep  them 


FIG.    10.     A 
mortar    shell    fitted    with 
tail-vanes 


from  tumbling  when  in  flight. 


CHAPTER  III 

GUNS  THAT  FIRE  THEMSELVES 

MANY  years  ago  a  boy  tried  his  hand  at 
firing  a  United  States  Army  service 
rifle.  It  was  a  heavy  rifle  of  the  Civil  War 
period,  and  the  lad  did  not  know  just  how  to 
hold  it.  He  let  the  butt  of  the  gun  rest  un- 
certainly against  him,  instead  of  pressing  it 
firmly  to  his  shoulder,  and,  in  consequence,  when 
the  gun  went  off  he  received  a  powerful  kick. 

That  kick  made  a  deep  impression  on  the 
lad,  not  only  on  his  flesh  but  on  his  mind  as 
well.  It  gave  him  a  good  conception  of  the 
power  of  a  rifle  cartridge. 

Years  afterward,  when  he  had  moved  to  Eng- 
land, the  memory  of  that  kick  was  still  with 
him.  It  was  a  useless  prank  of  the  gun,  he 
thought,  a  waste  of  good  energy.  Why  could 
not  the  energy  be  put  to  use?  And  so  he  set 
himself  the  task  of  harnessing  the  kick  of  the 
gun. 

41 


42       INVENTIONS  OF  THE  GREAT  WAR 

A  very  busy  program  he  worked  out  for  that 
kick  to  perform.  He  planned  to  have  the  gun 
use  up  its  exuberant  energy  in  loading  and  fir- 
ing itself.  So  he  arranged  the  cartridges  on  a 
belt  and  fed  the  belt  into  the  gun.  When  the 
gun  was  fired,  the  recoil  would  unlock  the  breech, 
take  out  the  empty  case  of  the  cartridge  just 
fired,  select  a  fresh  cartridge  from  the  belt,  and 
cock  the  main  spring ;  then  the  mechanism  would 
return,  throwing  the  empty  cartridge-case  out 
of  the  gun,  pushing  the  new  cartridge  into  the 
barrel,  closing  the  breech,  and  finally  pulling 
the  -trigger.  All  this  was  to  be  done  by  the 
energy  of  a  single  kick,  in  about  one  tenth  of  a 
second,  and  the  gun  would  keep  on  repeating  the 
operation  as  long  -as  the  supply  of  cartridges 
was  fed  to  it.  The  new  gun  proved  so  successful 
that  the  inventor  was  knighted,  and  became  Sir 
Hiram  Maxim. 


But  Maxim's  was  by  no  means  the  first  ma- 
chine-gun. During  the  Civil  War  a  Chicago 
physician  brought  out  a  very  ingenious  ten- 
barreled  gun,  the  barrels  of  which  were  fired 
one  after  the  other  by  the  turning  of  a  hand- 


GUNS  THAT  FIKE  THEMSELVES         43 

crank.  Although  Dr.  Galling  was  a  graduate 
of  a  medical  school,  he  was  far  more  fond  of 
tinkering  with  machinery  than  of  doling  out 
pills.  He  invented  a  number  of  clever  mechan- 
isms, but  the  -one  that  made  him  really  famous 
was  that -machine-gun.  At  first  our  government 
did  not  take  the  invention  seriously.  The  gun 
was  tried  out  in  the  war,  but  whenever  it  went 
into  battle  it  was  fired  not  by  soldiers  but  by  a 
representative  of  Dr.  (ratling's  company,  who 
went  into  the  army  to  demonstrate  the  worth  of 
the  invention.  Not  until  long  after  was  the 
Gatling  gun  officially  adopted  by  our  army. 
Then  it  was  taken  up  by  many  of  the  European 
armies  as  well. 

Although  many  other  machine-guns  were  in- 
vented, the  Gatling  was  easily  the  best  and  most 
serviceable,  until  the  Maxim  invention  made  its 
appearance,  and  even  then  it  held  its  own  for 
many  years ;  but  eventually  it  had  to  succumb. 
The  Maxim  did  not  have  to  be  cranked:  it 
fired  itself,  which  was  a  distinct  advantage; 
and  then,  instead  of  being  a  bundle  of  guns 
all  bound  up  into  a  single  machine,  Maxim's 
was  a  single-barreled  gun  and  hence  was  much 
lighter  and  could  be  handled  much  more  easily. 


44      INVENTIONS  OF  THE  GREAT  WAR 

A      GUN   AS   A   GAS-ENGINE 

Another  big  advance  was  made  by  a  third 
American,  Mr.  John  M.  Browning,  who  is  re- 
sponsible for  the  Colt  gun.  It  was  not  a  kick 
that  set  Browning  to  thinking.  He  looked  upon 
a  gun  as  an  engine  of  the  same  order  as  an 
automobile  engine,  and  really  the  resemblance 
is  very  close.  The  barrel  of  the  gun  is  the 
cylinder  of  the  engine;  the  bullet  is  the  piston; 
and  for  fuel  gunpowder  is  used  in  place  of  gaso- 
lene. As  in  the  automobile  engine,  the  charge 
is  fired  by  a  spark;  but  in  the  case  of  the  gun 
the  spark  is  produced  by  a  blow  of  the  trigger 
upon  a  bit  of  fulminate  of  mercury  in  the  end  of 
the  cartridge. 

Explosion  is  the  same  thing  as  burning.  The 
only  way  that  the  explosion  of  gunpowder  dif- 
fers from  the  burning  of  a  stick  of  wood  is  that 
the  latter  is  very  slow,  while  the  former  goes 
like  a  flash.  In  both  cases  the  fuel  turns  into 
great  volumes  of  gas.  In  the  case  of  the  gun 
the  gas  is  formed  almost  instantly  and  in  such 
quantity  that  it  has  to  drive  the  bullet  out  of 
the  barrel  to  make  room  for  itself.  In  the  cart- 
ridge that  our  army  uses,  only  about  a  tenth 


(C)  Committee  on  Public  Information 

Browning  Machine  Rifle,  weight  only  15  pounds 


(C)    Committee   on    Public   Information 

Browning  Machine  Gun,  weighing  34^  pounds 


GUNS  THAT  FIRE  THEMSELVES         45 

of  an  ounce  of  smokeless  powder  is  used,  but 
this  builds  up  so  heavy  a  pressure  of  gas  that 
the  bullet  is  sent  speeding  out  of  the  gun  at  a 
rate  of  half  a  mile  a  second.  It  travels  so  fast 
that  it  will  plow  -through  four  feet  of  solid  wood 
before  coming  to  a  stop. 

Now  it  occurred  to  Browning  that  it  wouldn't 
really  be  stealing  to  take  a  little  of  that  gas- 
power  and  use  it  to  work  the  mechanism  of  his 
machine-gun.  It  was  ever  so  little  he  wanted, 
and  the  bullet  would  never  miss  it.  The 
danger  was  not  that  he  might  take  too  much. 
His  problem  was  to  take  any  power  at  all  with- 
out getting  more  than  his  mechanism  could 
stand.  What  he  did  was  to  bore  a  hole  through 
the  side  of  the  gun-barrel.  When  the  gun  was 
fired,  nothing  happened  until  the  bullet  passed 
this  hole;  then  some  of  the  gas  that  was  push- 
ing the  bullet  before  it  would  blow  out  through 
the  hole.  But  this  would  be  a  very  small 
amount  indeed,  for  the  instant  that  the  bullet 
passed  out  of  the  barrel  the  gases  would  rush 
out  after  it,  the  pressure  in  the  gun  would  drop, 
and  -the  gas  would  stop  blowing  through  the 
hole.  With  the  bullet  traveling  at  the  rate  of 
about  half  a  mile  in  a  second,  imagine  how  short 


46       INVENTIONS  OF  THE  GREAT  WAR 

a  space  of  time  elapses  after  it  passes  the  hole 
before  it  emerges  from  the  muzzle,  and  what  a 
small  amount  of  gas  can  pass  through  the  hole 
in  that  brief  interval! 

The  gas  that  Browning  got  in  this  way  he 
led  into  a  second  cylinder,  fitted  with  a  piston. 
This  piston  was  given  a  shove,  and  that  gave 
a  lever  a  kick  which  set  going  the  mechanism 
that  extracted  the  empty  cartridge-case,  in- 
serted a  fresh  cartridge,  and  fired  it. 

GETTING   BID    OF    HEAT 

The  resemblance  of  a  machine-gun  to  a  gaso- 
lene-engine can  be  demonstrated  still  further. 
One  of  the  most  important  parts  of  an  auto- 
mobile engine  is  the  cooling-system.  The  gaso- 
lene burning  in  the  cylinders  would  soon  make 
them  red-hot,  were  not  some  means  provided 
to  carry  off  the  heat.  The  same  is  true  of  a 
machine-gun.  In  fact,  the  heat  is  one  of  the 
biggest  problems  that  has  to  be  dealt  with.  In 
a  gasolene-engine  the  heat  is  carried  off  in  one 
of  three  ways:  (1)  by  passing  water  around 
the  cylinders;  (2)  by  building  flanges  around 
the  cylinders  to  carry  the  heat  off  into  the  air; 
and  (3)  by  using  a  fan  to  blow  cool  air  against 


GUNS  THAT  FIKE  THEMSELVES         47 

the  cylinders.  All  of  these  schemes  are  used 
in  the  machine-gun.  In  Dr.  Gatling's  gun  'the 
cooling-problem  was  very  simple.  As  there 
were  ten  barrels,  one  barrel  could  be  cooling 
while  the  rest  were  taking  their  turn  in  the 
firing.  In  other  words,  each  barrel  received 
only  a  tenth  of  the  heat  that  the  whole  gun  was 
producing;  and  yet  Gatling  found  it  advisable 
to  surround  the  barrels  for  about  half  their 
length  with  a  water-jacket. 

In  the  Maxim  gun  a  water-jacket  is  used  that 
extends  the  full  length  of  the  barrel,  and  into 
this  waiter-jacket  seven  and  a  half  pints  of  water 
are  poured.  Yet  in  a  minute  and  a  half  of 
steady  firing  at  a  moderate  rate,  or  before  six 
hundred  rounds  are  discharged,  the  water  will 
be  boiling.  After  that,  with  every  thousand 
rounds  of  continuous  fire  a  pint  and  a  half  of 
water  will  be  evaporated.  Now  the  water  and 
the  water-jacket  add  a  great  deal  of  weight  to 
the  gun,  and  this  Browning  decided  to  do  away 
with  in  his  machine-gun.  Instead  of  water  he 
used  air  to  carry  off  the  heat.  The  more  sur- 
face the  air  touches,  the  more  heat  will  it  carry 
away;  and  so  the  Golt  gun  was  at  first  made 
with  a  very  thick- walled  barrel.  But  later  the 


48       INVENTIONS  OF  THE  GREAT  WAR 

Colt  was  formed  with  flanges,  like  the  flanges 
on  a  motor-cycle  engine,  so  as  to  increase  the 
surface  of  the  barrel.  Of  course,  air-cooling  is 
not  so  effective  as  water-cooling,  but  it  is 
claimed  for  this  gun,  and  for  other  machine- 
guns  of  the  same  class,  that  the  barrel  is 
sufficiently  cooled  for  ordinary  service.  Al- 
though a  machine-gun  may  be  capable  of  firing 
many  hundred  shots  per  minute,  it  is  seldom 
that  such  a  rate  is  kept  up  very  long  in  battle. 
Usually,  only  a  few  rounds  are  fired  at  a  time 
and  then  there  is  a  pause,  and  there  is  plenty 
of  time  for  the  barrel  to  cool.  Once  in  a  while, 
however,  the  gun  has  to  be  fired  continuously 
for  several  minutes,  and  then  the  barrel  grows 
exceedingly  hot. 

EFFECT    OF    OVERHEATING 

But  what  if  the  gun-barrel  does  become  hot? 
The  real  trouble  is  not  that  the  cartridge  will 
explode  prematurely,  but  that  the  barrel  will 
expand  as  it  grows  hot,  so  that  the  bullet  will 
fit  too  loosely  in  the  bore.  Inside  the  barrel 
the  bore  is  rifled;  that  is,  there  are  spiral 
grooves  in  it  which  give  a  twist  to  the  bullet 
as  it  passes  through,  setting  it  spinning  like  a 


GUNS  THAT  FIRE  THEMSELVES         49 

top.  The  spin  of  the  bullet  keeps  its  nose  point- 
ing forward.  If  it  were  not  for  the  rifling,  the 
bullet  would  tumble  over  and  over,  every  which 
way,  and  it  could  not  go  very  far  through  the 
air,  to  say  nothing  of  penetrating  steel  armor. 
To  gain  the  spinning-motion  the  bullet  must 
fit  into  the  barrel  snugly  enough  to  squeeze 
into  the  spiral  grooves.  Now  there  is  another 
American  machine-gun  known  as  the  Hotchkiss, 
which  was  used  to  a  considerable  extent  by  the 
French  Army.  It  is  a  gas-operated  gun,  some- 
thing like  the  Colt,  and  it  is  air-cooled.  It  was 
found  in  tests  of  the  Hotchkiss  gun  that  in  from 
three  to  four  minutes  of  firing  the  barrel  was 
expanded  so  much  that  the  shots  began  to  be  a 
little  uncertain.  In  seven  minutes  of  con- 
tinuous firing  the  barrel  had  grown  so  large  that 
the  rifling  failed  to  grip  the  bullet  at  all.  The 
gun  was  no  better  than  an  old-fashioned 
smooth-bore.  The  bullets  would  not  travel 
more  than  three  hundred  yards.  It  is  because 
of  this  danger  of  overheating  that  the  Colt  and 
the  Hotchkiss  guns  are  always  furnished  with  a 
spare  barrel.  As  soon  as  a  barrel  gets  hot  it  is 
uncoupled  and  the  spare  one  is  inserted  in  its 
place.  Our  men  are  trained  to  change  the 


50       INVENTIONS  OF  THE  GREAT  WAR 

barrel  of  a  colt  in  the  dark  in  a  quarter  of  a 
minute. 

But  a  gun  that  has  to  have  a  spare  barrel 
and  that  has  to  have  its  barrel  changed  in  the 
midst  of  a  hot  engagement  is  not  an  ideal 
weapon,  by  any  means.  And  this  brings  us  to 
still  another  invention — that,  too,  by  an  Amer- 
ican. Colonel  I.  N.  Lewis,  of  the  United  States 
Army,  conceived  of  a  machine-gun  that  would  be 
cooled  not  by  still  air  but  by  air  in  motion.  This 
would  do  away  with  all  the  bother  of  water- 
jackets.  It  would  keep  the  gun  light  so  that 
it  could  be  operated  by  one  man,  and  yet  it 
would  not  have  to  be  supplied  with  a  spare 
barrel. 

Like  the  Colt  and  the  Hotchkiss,  the  Lewis 
gun  takes  its  power  from  the  gas  that  comes 
through  a  small  port  in  the  barrel,  near  the 
muzzle.  In  the  plate  facing  page  44  the  port 
may  be  seen  leading  into  a  cylinder  that  lies 
under  the  barrel.  It  takes  about  one  ten- 
thousandth  part  of  a  second  for  a  bullet  to 
pass  out  of  the  barrel  after  clearing  the  port, 
but  in  that  brief  interval  there  is  a  puff  of 
gas  in  the  cylinder  which  drives  back  a  pis- 
ton. This  piston  has  teeth  on  it  which  en- 


GUNS  THAT  FIRE  THEMSELVES         51 

gage  a  small  gear  connected  with  a  main- 
spring. When  the  piston  moves  back,  it  winds 
the  spring,  and  it  is  this  spring  that  operates 
the  mechanism  of  the  gun.  The  cartridges,  in- 
stead of  being  taken  from  a  belt  or  a  clip,  are 
taken  from  a  magazine  that  is  round  and  flat. 
There  are  forty-seven  cartridges  in  the  maga- 
zine and  they  are  arranged  like  the  spokes  of  a 
wheel,  but  in  two  layers.  As  soon  as  forty- 
seven  rounds  have  been  fired,  the  shooting  must 
stop  while  a  new  magazine  is  inserted.  But  to 
insert  it  takes  only  a  couple  of  seconds. 

USING   THE   BULLET    TO    FAN    THE   GUN 

The  most  ingenious  part  of  the  Lewis  gun 
is  the  cooling-system.  On  the  barrel  of  the  gun 
aro  sixteen  flanges  or  fins.  These,  instead  of 
running  around  the  gun,  run  lengthwise  of  the 
barrel.  They  are  very  light  fins,  being  made 
of  aluminum,  and  are  surrounded  by  a  cas- 
ing of  the  same  metal.  The  casing  is  open  at 
each  end  so  that  the  air  can  flow  through  it, 
but  it  extends  beyond  the  muzzle  of  the  barrel, 
and  there  it  is  narrowed  down.  At  the  end  of 
the  barrel  there  is  a  mouthpiece  so  shaped  that 
the  bullet,  as  it  flies  through,  sucks  a  lot  of  air 


52      INVENTIONS  OF  THE  GREAT  WAR 

in  its  wake,  making  a  strong  current  flow 
through  the  sixteen  channels  formed  between 
the  fins  inside  the  casing.  This  air  flows  at  the 
rate  of  about  seventy  miles  per  hour,  which  is 
enough  to  carry  off  all  the  heat  that  is  generated 
by  the  firing  of  the  cartridges.  The  gun  may 
be  regulated  to  fire  between  350  and  750  rounds 
per  minute,  and  its  total  weight  is  only  25% 
pounds. 

America  can  justly  claim  the  honor  of  invent- 
ing and  developing  the  machine-gun,  although 
Hiram  Maxim  did  give  up  his  American  citizen- 
ship and  become  a  British  subject.  By  the  way, 
he  is  not  to  be  confused  with  his  younger 
brother,  Hudson  Maxim,  the  inventor  of  high 
explosives,  who  has  always  been  an  American 
to  the  core.  Of  course  we  must  not  get  the  im- 
pression that  only  Americans  have  invented 
machine-guns.  There  have  been  inventors  of 
such  weapons  in  various  countries  of  Europe, 
and  even  in  Japan.  Our  own  army  for  a  while 
used  a  gun  known  as  the  Benet-Mercie,  which 
is  something  like  the  Hotchkiss.  This  was  in- 
vented by  L.  V.  Benet,  an  American,  and  H.  A. 
Mercie,  a  Frenchman,  both  living  in  St.  Denis, 
France. 


Lewis  Machine-guns  in  action  at  the  front 


GUNS  THAT  FIRE  THEMSELVES         53 

THE   BROWNING   MACHINE-GUN 

When  we  entered  the  war,  it  was  expected 
that  we  would  immediately  equip  our  forces 
with  the  Lewis  gun,  because  the  British  and  the 
Belgians  had  found  it  an  excellent  weapon  and 
also  because  it  was  invented  by  an  American 
officer,  who  very  patriotically  offered  it  to  our 
government  without  charging  patent  royalties. 
But  the  army  officials  would  not  accept  it, 
although  many  Lewis  guns  were  bought  by  the 
navy.  This  raised  a  storm  of  protest  through- 
out the  country  until  finally  it  was  learned  that 
there  was  another  gun  for  which  the  army  was 
waiting,  which  it  was  said  would  be  the  very 
best  yet.  The  public  was  skeptical  and  finally 
a  test  was  arranged  in  Washington  at  which  the 
worth  of  the  new  gun  was  demonstrated. 

It  was  a  new  Browning  model;  or,  rather, 
there  were  two  distinct  models.  One  of  them, 
known  as  the  heavy  model,  weighed  only  34% 
pounds,  this  with  its  water-jacket  filled;  for  it 
was  a  water-cooled  gun.  Without  its  charge  of 
water  the  machine  weighed  but  22%  pounds  and 
could  be  rated  as  a  very  light  machine-gun. 
However,  it  was  classed  as  a  heavy  gun  and  was 


54      INVENTIONS  OF  THE  GREAT  WAR 

operated  from  a  tripod.  The  new  machine  used 
recoil  to  operate  its  mechanism.  The  construc- 
tion was  simple,  there  were  few  parts,  and  the 
gun  could  very  quickly  be  taken  apart  in  case 
of  breakage  or  disarrangement  of  the  mechan- 
ism. But  the  greatest  care  was  exercised  to 
prevent  jamming  of  cartridges,  which  was  one 
of  the  principal  defects  in  the  other  types  of 
machine-guns.  In  the  test  this  new  weapon 
fired  twenty  thousand  shots  at  the  rate  of  six 
hundred  per  minute,  with  interruptions  of  only 
four  and  a  half  seconds,  due  partly  to  defective 
cartridges. 

There  was  no  doubt  that  the  new  Browning 
was  a  remarkable  weapon.  But  if  that  could 
be  said  of  the  heavy  gun,  the  light  gun  was  a 
marvel.  It  weighed  only  fifteen  pounds  and 
was  light  enough  to  be  fired  from  the  shoulder 
or  from  the  hip,  while  the  operator  was  walk- 
ing or  running.  In  fact,  it  was  really  a  ma- 
chine-rifle. The  regular  .30-caliber  service 
cartridges  were  used,  and  these  were  stored  in 
a  clip  holding  twenty  cartridges.  The  cart- 
ridges could  be  fired  one  at  a  time,  or  the  entire 
clip  could  be  fired  in  two  and  a  half  seconds.  It 
took  but  a  second  to  drop  an  empty  clip  out  of 


GUNS  THAT  FIRE  THEMSELVES         55 

the  gun  and  replace  it  with  a  fresh  one.  The 
rifle  was  gas-operated  and  air-cooled,  but  no 
special  cooling-device  was  supplied  because  it 
would  seldom  be  necessary  to  fire  a  shoulder 
rifle  fast  enough  and  long  enough  for  the  barrel 
to  become  overheated. 

After  the  Browning  machine-rifle  was  demon- 
strated it  was  realized  that  the  army  had  been 
perfectly  justified  in  waiting  for  the  new 
weapon.  Like  the  heavy  Browning,  the  new 
rifle  was  a  very  simple  mechanism,  with  few 
parts  which  needed  no  special  tools  to  take  them 
apart  or  reassemble  them ;  a  single  small  wrench 
served  this  purpose.  Both  the  heavy  and  the 
light  gun  were  proof  against  mud,  sand,  and 
dust  of  the  battle-field.  But  best  of  all,  a  man 
did  not  have  to  have  highly  specialized  training 
before  he  could  use  the  Browning  rifle.  It  did 
not  require  a  crew  to  operate  one  of  these  guns. 
Each  soldier  could  have  his  own  machine-gun 
and  carry  it  in  a  charge  as  he  would  a  rifle. 
The  advantage  of  the  machine-rifle  was  that  the 
operator  could  fire  as  he  ran,  watching  where 
the  bullets  struck  the  ground  by  noting  the  dust 
they  kicked  up  and  in  that  way  correcting  his 
aim  until  he  was  on  the  target.  Very  accurate 


56   INVENTIONS  OF  THE  GREAT  WAR 

shooting  was  thus  made  possible,  and  the  ma- 
chine-rifle proved  invaluable  in  the  closing 
months  of  the  war. 

Browning  is  unquestionably  the  foremost  in- 
ventor of  firearms  in  the  world.  He  was  born 
of  Mormon  parents,  in  Ogden,  Utah,  in  1854, 
and  his  father  had  a  gun  shop.  As  a  boy 
Browning  became  familiar  with  the  use  of  fire- 
arms and  when  he  was  but  fourteen  years  of 
age  he  invented  an  improved  breech  mechanism 
which  was  later  used  in  the  Winchester  repeater. 
Curiously  enough,  it  was  a  Browning  pistol  that 
was  used  by  the  assassin  at  Serajevo  who  killed 
the  Archduke  of  Austria  and  precipitated  the 
great  European  war, -and  it  was  with  the  Brown- 
ing machine-gun  and  rifle  that  our  boys  swept 
the  Germans  back  through  the  Argonne  For- 
est and  helped  to  bring  the  war  to  a  successful 
end. 

THE   MACHINE-GUN    IN    SERVICE 

Although  the  machine-gun  has  been  used  ever 
since  the  Civil  War,  it  was  not  a  vital  factor  in 
warfare  until  the  recent  great  conflict.  Army 
officials  were  very  slow  to  take  it  up,  because 
they  did  not  understand  it.  They  used  to  think 


GUNS  THAT  FIRE  THEMSELVES         57 

of  it  as  an  inferior  piece  of  light  artillery,  in- 
stead of  a  superior  rifle.  The  Gatling  was  so 
heavy  that  it  had  to  be  mounted  on  wheels,  and 
naturally  it  was  thought  of  as  a  cannon.  In 
the  Franco-Prussian  War  the  French  had  a  ma- 
chine-gun by  which  they  set  great  store.  It  was 
called  a  mitrailleuse,  or  a  gun  for  firing  grape- 
shot.  It  was  something  like  the  Gatling.  The 
French  counted  on  this  machine  to  surprise 
and  overwhelm  the  Germans.  But  they  made 
the  mistake  of  considering  it  a  piece  of  artil- 
lery and  fired  it  from  long  range,  so  that  it  did 
not  have  a  chance  to  show  its  worth.  Only  on 
one  or  two  occasions  was  it  used  at  close 
range,  and  then  it  did  frightful  execution. 
However,  it  was  a  very  unsatisfactory  machine, 
and  kept  getting  out  of  order.  It  earned  the 
contempt  of  the  Germans,  and  later  when  the 
Maxim  gun  was  offered  to  the  German  Army 
they  would  have  none  of  it.  They  did  not  want 
to  bother  with  "a  toy  cannon." 

It  really  was  not  until  the  war  between  Eus- 
sia  and  Japan  that  military  men  began  to  real- 
ize the  value  of  the  machine-gun.  As  the  war 
went  on,  both  the  Eussians  and  the  Japanese 
bought  up  all  the  machine-guns  they  could  se- 


58       INVENTIONS  OF  THE  GREAT  WAR 

cure.  They  learned  what  could  be  done  with 
the  aid  of  barbed  wire  to  retard  the  enemy  while 
the  machine-guns  mowed  them  down  as  they 
were  trying  to  get  through. 

A  man  with  a  machine-gun  is  worth  a  hun- 
dred men  with  rifles;  such  is  the  military  esti- 
mate of  the  weapon.  The  gun  fires  so  fast  that 
after  hitting  a  man  it  will  hit  him  again  ten 
times  while  he  is  falling  to  the  ground.  And 
so  it  does  not  pay  to  fire  the  gun  continuously 
in  one  direction,  unless  there  is  a  dense  mass  of 
troops  charging  upon  it.  Usually  the  machine- 
gun  is  swept  from  side  to  side  so  as  to  cover 
as  wide  a  range  as  possible.  It  is  played  upon 
the  enemy  as  you  would  play  the  hose  upon  the 
lawn,  scattering  a  shower  of  lead  among  the 
advancing  hosts. 

MACHINE-GUN    FOETS 

It  used  to  be  thought  that  the  Belgian  forts  of 
armored  steel  and  concrete,  almost  completely 
buried  in  the  ground,  would  hold  out  against 
any  artillery.  But  when  the  Germans  brought 
up  their  great  howitzers  and  hurled  un- 
dreamed-of quantities  of  high  explosives  on 
these  forts,  they  broke  and  crumbled  to  pieces. 


GUNS  THAT  FIRE  THEMSELVES         59 

Then  it  was  predicted  that  the  day  of  the  fort 
was  over.  But  the  machine-gun  developed  a 
new  type  of  warfare.  Instead  of  great  forts, 
mounting  huge  guns,  little  machine-gun  forts 
were  built,  and,  they  were  far  more  troublesome 
than  the  big  fellows. 

To  the  Germans  belongs  the  credit  for  the  new 
type  of  fort,  which  consisted  of  a  small  concrete 
structure,  hidden  from  view  as  far  as  possible, 
but  commanding  some  important  part  of  the 
front.  "  Pill-boxes, "  the  British  call  them,  be- 
cause the  first  ones  they  ran  across  were  round 
in  shape  and  something  like  a  pill-box  in  ap- 
pearance. These  pill-boxes  were  just  large 
enough  to  house  a  few  men  and  a  couple  of 
machine-guns.  Concealment  was  of  the  utmost 
importance;  safety  depended  upon  it.  Air- 
planes were  particularly  feared,  because  a  ma- 
chine-gun emplacement  was  recognized  to  be 
so  important  that  a  whole  battery  of  artillery 
would  be  turned  upon  a  suspected  pill-box. 

Some  of  the  German  machine-gun  forts  were 
very  elaborate,  consisting  of  spacious  under- 
ground chambers  where  a  large  garrison  of 
gunners  could  live.  These  forts  were  known 
as  Mebus,  a  word  made  from  the  initials  of 


60      INVENTIONS  OF  THE  GREAT  WAR 

"Maschinengewehr  Eisen-Bettungs  Unter- 
stand,"  meaning  a  machine-gun  iron-bedded 
foundation. 

It  was  the  machine-gun  that  was  responsible 
for  the  enormous  expenditure  of  ammunition  in 
the  war.  Before  a  body  of  troops  dared  to 
make  a  charge,  the  ground  had  to  be  thoroughly 
searched  by  the  big  guns  for  any  machine-gun 
nests.  Unless  these  were  found  and  destroyed 
by  shell-fire,  the  only  way  that  remained  to  get 
the  best  of  them  was  to  crush  them  down  with 
tanks.  It  was  really  the  machine-gun  that 
drove  the  armies  into  trenches  and  under  the 
ground. 

But  a  machine-gun  did  not  have  to  be  housed 
in  a  fort,  particularly  a  light  gun  of  the  Lewis 
type.  To  be  sure,  the  Lewis  gun  is  a  little 
heavy  to  be  used  as  a  rifle,  but  it  could  easily 
be  managed  with  a  rest  for  the  muzzle  in  the 
crotch  of  a- tree,  and  a  strong  man  could  actually 
fire  the  piece  from  the  shoulder.  The  light  ma- 
chine-gun could  go  right  along  with  a  charging 
body  of  troops  and  do  very  efficient  service,  par- 
ticularly in  fighting  in  a  town  or  village,  but  it 
had  to  be  kept  moving  or  it  would  be  a  target 
for  the  artillery.  In  a  certain  village  fight  a 


GUNS  THAT  FIRE  THEMSELVES         61 

machine-gunner  kept  changing  his  position. 
He  would  fire  for  a  few  minutes  from  one  build- 
ing and  then  shift  over  to  some  other.  He  did 
this  no  less  than  six  times,  never  staying  more 
than  five  minutes  at  a  time  in  the  same  spot. 
But  each  one  of  the  houses  was  shelled  within 
fifteen  minutes  of  the  time  he  opened  fire  from 
it,  which  shows  the  importance  that  the  Ger- 
mans attached  to  machine-gun  fire. 


CHAPTEE  IV 

GUNS   AND    SUPER-GUNS 

WHEN  the  news  came  that  big  shells  were 
dropping  into  Paris  from  a  gun  which 
must  be  at  least  seventy  miles  away,  the  world 
at  first  refused  to  believe;  then  it  imagined 
that  some  brand-new  form  of  gun  or  shell 
or  powder  had  been  invented  by  the  Germans. 
However,  while  the  public  marveled,  ordnance 
experts  were  interested  but  not  astonished. 
They  knew  that  it  was  perfectly  feasible  to  build 
a  gun  that  would  hurl  a  shell  fifty,  or  seventy- 
five,  or  even  a  hundred  miles,  without  involving 
anything  new  in  the  science  of  gunnery. 

SHOOTING   ABOUND   THE   EDGE   OF   THE   EAKTH 

But  if  such  ranges  were  known  to  be  possible, 
why  was  no  such  long-distance  gun  built  before? 
Simply  because  none  but  the  Germans  would 
ever  think  of  shooting  around  the  edge  of  the 
earth  at  a  target  so  far  away  that  it  would 

62 


GUNS  AND  SUPER-GUNS  63 

have-  to  be  as  big  as  a  whole  city  to  be  hit  at 
all.  In  a  distance  of  seventy  miles,  the  curve 
of  ihe  earth  is  considerable.  Paris  is  far  be- 
low the  horizon  of  a  man  standing  at  St.  Go- 
bain,  where  the  big  German  gun  was  located. 
And  if  a  hole  were  bored  from  St.  Gobain 
straight  to  Paris,  so  that  you  could  see  the  city 
from  the  gun,  it  would  pass,  midway  of  its 
course,  -three-  thousand,  seven  hundred  and  fifty 
feet  below  the  surface  of  the  earth.  With  the 
target  so  far  off,  it  was  impossible  to  aim  at  any 
particular  fort,  ammunition  depot,  or  other 
point  of  military  importance.  There  is  always 
some  uncertainty  as  to  just  where  a  shell  will 
fall,  due  to  slight  differences  in  quality  and 
quantity  of  the  powder  used,  in  the  density  of 
the  air,  the  direction  of  the  wind,  etc.  This 
variation  is  bad  enough  when  a  shell  is  to  be 
fired  ten  miles,  but  when  the  missile  has  to 
travel  seventy  miles,  it  is  out  of  the  question 
to  try  to  hit  a  target  that  is  not  miles  in  extent. 
Twenty  years  before  the  war  our  Ordnance 
Department  had  designed  a  fifty-mile  gun,  but 
it  was  not  built,  because  we  could  see  no  possi- 
ble use  for  it.  Our  big  guns  were  built  for  fight- 
ing naval  battles  or  for  the  defense  of  our  coasts 


64       INVENTIONS  OF  THE  GREAT  WAR 

from  naval  attacks,  and  there  is  certainly  no  use 
in  firing  at  a  ship  that  is  so  far  below  the  horizon 
that  we  cannot  even  see  the  tips  of  its  masts; 
and  so  our  big  guns,  though  they  were  capable 
of  firing  a  shell  twenty-seven  miles,  if  aimed 
high  enough,  were  usually  mounted  in  carriages 
that  would  not  let  them  shoot  more  than  twelve 
or  fifteen  miles. 

The  distance  to  which  a  shell  can  be  hurled 
depends  to  a  large  extent  upon  the  angle  of  the 
gun.  If  the  gun  is  tilted  up  to  an  angle  of  15 
degrees,  the  shell  will  go  only  about  half  as 
far  as  if  it  were  tilted  up  to  43  V£  degrees,  which 
is  the  angle  that  will  carry  a  shell  to  its  great- 
est distance.  If  the  long-range  German  gun 
was  fired  at  that  angle,  the  shell  must  have 
risen  to  a  height  of  about  twenty-four  miles. 

BEYOND   THE   EARTH  ?S   ATMOSPHERE 

Most  of  the  air  that  surrounds  our  globe  lies 
within  four  miles  of  the  surface.  Few  airplanes 
can  rise  to  a  greater  height  than  this,  because 
the  air  is  so  thin  that  it  gives  no  support  to  the 
wings  of  the  machine.  The  greatest  height  to 
which  a  man  has  ever  ascended  is  seven  miles. 
A  balloon  once  carried  two  men  to  such  a  height. 


GUNS  AND  SUPER-GUNS  65 

One  of  them  lost  consciousness,  and  the  other, 
who  was  nearly  paralyzed,  succeeded  in  pulling 
the  safety-valve  rope  with  his  teeth.  That 
brought  the  balloon  down,  and  their  instruments 
showed  that  they  had  gone  up  thirty-six,  thou- 
sand feet.  What  the  ocean  of  air  contains  above 
that  elevation,  we  do  not  know,  but  judging  by 
the  way  the  atmosphere  thins  out  as  we  rise 
from  the  surface  of  the  earth,  we  reckon  that 
nine  tenths  of  the  air  lies  within  ten  miles  of 
the  surface  of  the  earth.  At  twenty-four  miles, 
or  the  top  of  the  curve  described  by  the  shell 
of  the  German  long-range  guns,  there  must  be 
an  almost  complete  vacuum. 

If  only  we  could  accompany  a  shell  on  its 
course,  we  should  find  a  strange  condition  of 
affairs.  The  higher  we  rose,  the  darker  would 
the  heavens  become,  until  the  sun  would  shine 
like  a  fiery  ball  in  a  black  sky.  All  around,  the 
stars  would  twinkle,  and  below  would  be  the 
glare  of  light  reflected  from  the  earth's  surface 
and  its  atmosphere,  while  the  cold  would  be  far 
more  intense  than  anything  suffered  on  earth. 
Up  at  that  height,  there  would  be  nothing  to  in- 
dicate that  the  shell  was  moving — no  rush  of 
air  against  the  ears.  We  should  seem  detached 


66       INVENTIONS  OF  THE  GREAT  WAR 

from  earth  and  out  in  the  endless  reaches  of 
space. 

It  seems  absurd  to  think  that  a  shell  weighing 
close  to  a  quarter  of  a  ton  could  be  retarded 
appreciably  by  mere  air.  But  when  we  realize 
that  the  shell  left  the  gun  at  the  rate  of  over 
half  a  mile  a  second — traveling  about  thirty 
times  faster  than  an  express-train — we  know 
that  the  air-pressure  mounts  up  to  a  respectable 
figure.  The  pressure  is  the  same  whether  a 
shell  is  moving  through  the  air  or  the  air  is 
blowing  against  the  shell.  When  the  wind 
blows  at  the  rate  of  100  to  120  miles  per  hour, 
it  is  strong  enough  to  lift  houses  off  their  foun- 
dations, to  wrench  trees  out  of  the  ground,  to 
pick  up  cattle  and  carry  them  sailing  through 
the  air.  Imagine  what  it  would  do  if  its  ve- 
locity were  increased  to  1,800  miles  per  hour. 
That  is  what  the  shell  of  a  big  gun  has  to  con- 
tend with.  As  most  of  the  air  lies  near  the 
earth,  the  shell  of  long-range  guns  meet  with 
less  and  less  resistance  the  higher  they  rise, 
until  they  get  up  into  such  thin  air  that  there 
is  virtually  no  obstruction.  The  main  trouble 
is  to  pierce  the  blanket  of  heavy  air  that  lies 
near  the  earth. 


GUNS  AND  SUPER-GUNS  67 

WAYS   OF   INCREASING   THE   BANGE 

The  big  16-inch  guns  that  protect  our  coasts 
fire  a  shell  that  weighs  2,400  pounds.  Nine 
hundred  pounds  of  smokeless  powder  is  used  to 
propel  the  shell,  which  leaves  the  muzzle  of  the 
gun  with  a  speed  of  2,600  feet  per  second.  Now, 
the  larger  the  diameter  of  the  shell,  the  greater 
will  be  its  speed  at  the  muzzle  of  the  gun,  be- 
cause there  will  be  a  greater  surface  for  the 
powder  gases  to  press  against.  On  the  other 
hand,  the  larger  the  shell,  the  more  will  it  be 
retarded  by  the  air,  because  there  will  be  a 
larger  surface  for  the  air  to  press  against.  It 
has  been  proposed  by  some  ordnance  experts 
that  a  shell  might  be  provided  with  a  disk  at 
each  end,  which  would  make  it  fit  a  gun  of  larger 
caliber.  A  10-inch  shell,  for  instance,  could 
then  be  fired  from  a  16-inch  gun.  Being  lighter 
than  the  16-inch  shell,  it  would  leave  the  muzzle 
of  the  gun  at  a  higher  speed.  The  disks  could 
be  so  arranged  that  as  soon  as  the  shell  left 
the  gun  they  would  be  thrown  off,  and  then  the 
10-inch  shell,  although  starting  with  a  higher 
velocity  than  a  16-inch  shell,  would  offer  less 
resistance  to  the  air.  In  that  way  it  could  be 


68      INVENTIONS  OF  THE  GREAT  WAR 

made  to  cover  a  much  greater  range.  By  the 
way,  the  shell  of  the  German  long-range  gun 
was  of  but  8.2-inch  caliber. 

Another  way  of  increasing  the  range  is  to 
lengthen  the  gun.  Eight  here  we  must  become 
acquainted  with  the  word  "  caliber. "  Caliber 
means  the  diameter  of  the  shell.  A  16-inch  gun, 
for  instance,  fires  a  shell  of  16-inch  caliber ;  but 
when  we  read  that  the  gun  is  a  40-  or  50-caliber 
gun,  it  means  that  the  length  of  the  gun  is  forty 
or  fifty  times  the  diameter  of  the  shell.  Our 
biggest  coast-defense  guns  are  50-caliber  16- 
inch  guns,  which  means  that  they  are  fifty  times 
16  inches  long,  or  66%  feet  in  length.  When  a 
gun  is  as  long  as  that,  care  has  to  be  taken  to 
prevent  it  from  sagging  at  the  muzzle  of  its  own 
weight.  These  guns  actually  do  sag  a  little, 
and  when  the  shell  is  fired  through  the  long 
barrel  it  straightens  up  the  gun,  making  the 
muzzle  "whip"  upward,  just  as  a  drooping 
garden  hose  does  when  the  water  shoots  through 
it. 

Now  the  longer  the  caliber  length  of  a  gun, 
the  farther  it  will  send  a  shell,  because  the  pow- 
der gases  will  have  a  longer  time  to  push  the 
shell.  But  we  cannot  lengthen  our  big  guns 


GUNS  AND  SUPER,GUNS  69 

much  more  without  using  some  special  support 
for  the  muzzle  end  of  the  gun,  to  keep  it  from 
"  whipping "  too  much.  It  is  likely  that  the 
long-range  German  gun  was  provided  with  a 
substantial  support  at  the  muzzle  to  keep  it 
from  sagging. 

Every  once  in  a  while  a  man  comes  forth  with 
a  "new  idea"  for  increasing  the  range.  One 
plan  is  to  increase  the  powder-pressure.  We 
have  powders  that  will  produce  far  more  pres- 
sure than  an  ordinary  gun  can  stand.  But  we 
have  to  use  powders  that  will  burn  compara- 
tively slowly.  We  do  not  want  too  sudden  a 
shock  to  start  with,  but  we  wish  the  powder 
to  give  off  an  enormous  quantity  of  gas  which 
will  keep  on  pushing  and  speeding  up  the  shell 
until  the  latter  emerges  from  the  muzzle.  The 
fifty-mile  gun  that  was  proposed  twenty  years 
ago  was  designed  to  stand  a  much  higher  pres- 
sure than  is  commonly  used,  and  it  would  have 
fired  a  10-inch  shell  weighing  600  pounds  with 
a  velocity  of  4,000  feet  per  second  at  the  muzzle. 

The  Allies  built  no  "super-guns,"  because 
they  knew  that  they  could  drop  a  far  greater 
quantity  of  explosives  with  much  greater  ac- 
curacy from  airplanes,  and  at  a  much  lower 


70       INVENTIONS  OF  THE  GREAT  WAR 

cost.  The  German  gun  at  St.  Gobain  was  spec- 
tacular and  it  did  some  damage,  but  it  had  no 
military  value  and  it  did  not  intimidate  the 
French  as  the  Germans  had  hoped  it  would. 

A   GUN    WITH   A   RANGE   OF   A   HUNDRED   AND 
TWENTY   MILES 

But  although  we  built  no  such  gun,  after  the 
Germans  began  shelling  Paris  our  Ordnance 
Department  designed  a  gun  that  would  fire  a 
shell  to  a  distance  of  over  120  miles!  There 
was  no  intention  of  constructing  the  gun,  but 
the  design  was  worked  out  just  as  if  it  were 
actually  to  be  built.  It  was  to  fire  a  shell  of 
10-inch  caliber,  weighing  400  pounds.  Now,  an 
Elswick  standard  10-inch  gun  is  42  feet  long 
and  its  shell  weighs  500  pounds.  Two  hundred 
pounds  of  powder  are  used  to  propel  the  shell, 
which  leaves  the  muzzle  with  a  velocity  of  3,000 
feet  per  second.  If  the  gun  is  elevated  to  the 
proper  angle,  it  will  send  the  shell  25  miles,  and 
it  will  take  the  shell  a  minute  and  thirty-seven 
seconds  to  cover  that  distance.  But  the  long- 
range  gun  our  ordnance  experts  designed  would 
have  to  be  charged  with  1,440  pounds  of  powder 
and  the  shell  would  leave  the  muzzle  of  the  gun 


GUNS  AND  SUPER-GUNS  71 

with  a  velocity  of  8,500  feet  per  second.  It 
would  be  in  the  air  four  minutes  and  nine  sec- 
onds and  would  travel  121.3  miles.  Were  the 
gun  fired  from  the  Aberdeen  Proving  Grounds, 
near  Baltimore,  Maryland,  its  shell  would  travel 
across  three  states  and  fall  into  New  York  Bay 
at  Perth  Amboy.  At  the  top  of  its  trajectory 
it  would  rise  46  miles  above  the  earth. 

But  the  most  astonishing  part  of  the  design 
was  the  length  of  the  gun,  which  worked  out  to 
225  feet.  An  enormous  powder-chamber  would 
have  to  be  used,  so  that  the  powder  gases  would 
keep  speeding  up  the  shell  until  it  reached  the 
required  velocity  at  the  muzzle.  The  weight 
of  the  barrel  alone  was  estimated  at  325  tons. 

It  would  have  to  be  built  up  in  four  sections 
screwed  together  and  because  of  its  great 
length  and  weight  it  would  have  to  be  supported 
on  a  steel  truss.  The  gun  would  be  mounted 
like  a  roller  lift-bridge  with  a  heavy  counter- 
weight at  its  lower  end  so  that  it  could  be  ele- 
vated or  depressed  at  will  and  a  powerful  hy- 
draulic jack  would  be  required  to  raise  it. 

The  recoil  of  a  big  gun  is  always  a  most  im- 
portant matter.  Unless  a  gun  can  recoil,  it 
will  be  smashed  by  the  shock  of  the  powder  ex- 


72      INVENTIONS  OF  THE  GREAT  WAR 

plosion.  Usually,  heavy  springs  are  used  to 
take  up  the  shock,  or  cylinders  filled  with  oil  in 
which  pistons  slide.  The  pistons  have  small 
holes  in  them  through  which  the  oil  is  forced 
as  the  piston  moves  and  this  retards  the  gun 
in  its  recoil.  But  this  "  super-gun "  was  de- 
signed to  be  mounted  on  a  carriage  running 
on  a  set  of  tracks  laid  in  a  long  concrete  pit. 
On  the  recoil  the  gun  would  run  back  along 
the  tracks,  and  its  motion  would  be  retarded  by 
friction  blocks  between  the  carriage  and  the 
tracks  and  also  by  a  steel  cable  attached  to  the 
forward  end  of  the  carriage  and  running  over 
a  pulley  on  the  front  wall  of  the  pit,  to  a  fric- 
tion drum. 

The  engraving  facing  page  68  gives  some  idea 
of  the  enormous  size  of  the  gun.  Note  the  man 
at  the  breech  of  the  gun.  The  hydraulic  jack 
is  collapsible,  so  that  the  gun  may  be  brought 
to  the  horizontal  position  for  loading,  as  shown 
by  the  dotted  lines.  The  cost  of  building  this 
gun  is  estimated  at  two  and  a  half  million  dol- 
lars and  its  400-pound  shell  would  land  only 
about  sixty  pounds  of  high  explosives  on  the 
target.  A  bombing-plane  costing  but  thirty 
thousand  dollars  could  land  twenty-five  times 


GUNS  AND  SUPER-GUNS  73 

as  big  a  charge  of  high  explosives  with  far 
greater  accuracy.  Aside  from  this,  the  gun 
lining  would  soon  wear  out  because  of  the  tre- 
mendous erosion  of  the  powder  gases. 

THE   THREE-SECOND   LIFE   OF   A   GUN 

Powder  gases  are  very  hot  indeed — hot 
enough  to  melt  steel.  The  greater  the  pressure 
in  the  gun,  the  hotter  they  are.  It  is  only  be- 
cause they  pass  through  the  gun  so  quickly, 
that  they  do  not  melt  it.  As  a  matter  of  fact, 
they  do  wear  it  out  rapidly  because  of  their 
heat  and  velocity.  They  say  that  the  life  of  a 
big  gun  is  only  three  seconds.  Of  course,  a  shell 
passes  through  the  gun  in  a  very  minute  part 
of  a  second,  but  if  we  add  up  these  tiny  periods 
until  we  have  a  total  of  three  seconds,  during 
which  the  gun  may  have  fired  two  hundred 
rounds,  we  shall  find  that  the  lining  of  the  barrel 
is  so  badly  eroded  that  the  gun  is  unfit  for  ac- 
curate shooting,  and  it  must  go  back  to  the  shops 
for  a  new  inner  tube. 

ELASTIC   GUNS 

We  had  better  go  back  with  it  and  learn 
something  about  the  manufacture  of  a  big  gun. 


74       INVENTIONS  OF  THE  GREAT  WAR 

Guns  used  to  be  cast  as  a  solid  chunk  of  metal. 
Now  they  are  built  up  in  layers.  To  under- 
stand why  this  is  necessary,  we  must  realize 
that  steel  is  not  a  dead  mass,  but  is  highly  elas- 
tic— far  more  elastic  than  rubber,  although,  of 
course,  it  does  not  stretch  nor  compress  so  far. 
When  a  charge  of  powder  is  exploded  in  the 
barrel  of  a  gun,  it  expands  in  all  directions. 
Of  course,  the  projectile  yields  to  the  pressure 
of  the  powder  gases  and  is  sent  kiting  out  of  the 
muzzle  of  the  gun.  But  for  an  instant  before 
the  shell  starts  to  move,  an  enormous  force  is 
exerted  against  the  walls  of  the  bore  of  the 
gun,  and,  because  steel  is  elastic,  the  barrel  is 
expanded  by  this  pressure,  and  the  bore  is  ac- 
tually made  larger  for  a  moment,  only  to  spring 
back  in  the  next  instant.  You  can  picture  this 
action  if  you  imagine  a  gun  made  of  rubber; 
as  soon  as  the  powder  was  fired,  the  rubber 
gun  would  bulge  out  around  the  powder-cham- 
ber, only  to  collapse  to  its  normal  size  when 
the  pressure  was  relieved  by  the  discharge  of 
the  bullet. 

Nowr  every  elastic  body  has  what  is  called  its 
elastic  limit.  If  you  take  a  coil  spring,  you  can 
pull  it  out  or  you  can  compress  it,  and  it  will 


GUNS  AND  SUPER-GUNS  75 

always  return  to  its  original  shape,  unless  you 
pull  it  out  or  compress  it  beyond  a  certain 
point ;  that  point  is  its  elastic  limit.  The  same 
is  true  of  a  piece  of  steel :  if  you  stretch  it  be- 
yond a  certain  point,  it  will  not  return  to  its 
original  shape.  When  the  charge  of  powder 
in  a  cannon  exceeds  a  certain  amount,  it 
stretches  the  steel  beyond  its  elastic  limit,  so 
that  the  bore  becomes  permanently  larger. 
Making  the  walls  of  the  gun  heavier  would  not 
prevent  this,  because  steel  is  so  elastic  that  the 
inside  of  the  walls  expands  beyond  its  elastic 
limit  before  the  outside  is  affected  at  all. 

Years  ago  an  American  inventor  named 
Treadwell  worked  out  a  scheme  for  allowing  the 
bore  to  expand  more  without  exceeding  its  elas- 
tic limit.  He  built  up  his  gun  in  layers,  and 
shrunk  the  outer  layers  upon  the  inner  layers, 
just  as  a  blacksmith  shrinks  a  tire  on  a  wheel, 
so  that  the  inner  tube  of  the  gun  would  be 
squeezed,  or  compressed.  When  the  powder 
was  fired,  this  inner  layer  could  expand  farther 
without  danger,  because  it  was  compressed  to 
start  with.  The  built-up  gun  was  also  indepen- 
dently invented  by  a  British  inventor.  All 
modern  big  guns  are  built  up. 


76      INVENTIONS  OF  THE  GREAT  WAK 

HOW   BIG   GUNS   ABE    MADE 

The  inside  tube,  known  as  the  lining,  is  cast 
roughly  to  shape,  then  it  is  bored  out,  after 
which  it  is  forged  by  the  blows  of  a  powerful 
steam-hammer.  Of  course,  while  under  the 
hammer,  the  tube  is  mounted  on  a  mandrel,  or 
bar,  that  just  fits  the  bore.  The  metal  is  then 
softened  in  an  annealing  furnace,  after  which 
it  is  turned  down  to  the  proper  diameter  and  re- 
bored  to  the  exact  caliber.  The  diameter  of 
the  lining  is  made  three  ten-thousandths  of  an 
inch  larger  than  the  inside  of  the  hoop  or  sleeve 
that  fits  over  it.  This  sleeve,  which  is  formed 
in  the  same  way,  is  heated  up  to  800  degrees, 
or  until  its  inside  diameter  is  eight  tenths  of  an 
inch  larger  than  the  outside  diameter  of  the 
lining.  The  lining  is  stood  up  on  end  and  the 
sleeve  is  fitted  over  it.  Then  it  is  cooled  by 
means  of  water,  so  that  it  grips  the  lining  and 
compresses  it.  In  this  way,  layer  after  layer 
is  added  until  the  gun  is  built  up  to  the  proper 
size. 

Instead  of  having  a  lining  that  is  compressed 
by  means  of  sleeves  or  jackets,  many  big  guns 
are  wound  with  wire  which  is  pulled  so  tight  as 


i 


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MH       O 

f    o> 


GUNS  AND  SUPER-GUNS  77 

to  compress  the  lining.  The  gun-tube  is  placed 
in  a  lathe,  and  is  turned  so  as  to  wind  up  the  wire 
upon  it.  A  heavy  brake  on  the  wire  keeps  it 
drawn  very  tight.  This  wire,  also,  is  put  on  in 
layers,  so  that  each  layer  can  expand  consid- 
erably without  exceeding  its  elastic  limit.  Our 
big  16-inch  coast-defense  guns  are  wound  with 
wire  that  is  one  -tenth  of  an  inch  square.  The 
length  of  wire  on  one  gun  is  sufficient  to  reach 
all  the  way  from  New  York  to  Boston  with  fifty 
or  sixty  miles  of  wire  left  over. 

GUNS   THAT   PLAY   HIDE-AND-SEEK 

A  very  ingenious  invention  is  the  disappear- 
ing-mount  which  is  used  on  our  coast  fortifica- 
tions. By  means  of  this  a  gun  is  hidden  beyond 
its  breastworks  so  that  it  is  absolutely  invisible 
to  the  enemy.  In  this  sheltered  position  it  is 
loaded  and  aimed.  It  is  not  necessary  to  sight 
the  gun  on  the  target  as  you  would  sight  a  rifle. 
The  aiming  is  done  mathematically.  Off  at 
some  convenient  observation  post,  an  observer 
gets  the  range  of  the  target  and  telephones  this 
range  to  the  plotting-room,  where  a  rapid  cal- 
culation is  made  as  to  how  much  the  gun  should 
be  elevated  and  swung  to  the  right  or  the  left. 


78       INVENTIONS  OF  THE  GREAT  WAR 

This  calculation  is  then  sent  on  to  the  gunners, 
who  adjust  the  gun  accordingly.  When  all  is 
ready,  the  gun  is  raised  by  hydraulic  pressure, 
and  just  as  it  rises  above  the  parapet  it  is  auto- 
matically fired.  The  recoil  throws  the  gun  back 
to  its  crouching  position  behind  the  breastworks. 
All  that  the  enemy  sees,  if  anything,  is  the  flash 
of  the  discharge. 

Now  that  airplanes  have  been  invented,  the 
disappearing-mount  has  lost  much  of  its  useful- 
ness. Big  guns  have  to  be  hidden  from  above. 
They  are  usually  located  behind  a  hill,  five  or  six 
miles  back  of  the  trenches,  where  the  enemy  can- 
not see  them  from  the  ground,  and  they  are  care- 
fully hidden  under  trees  or  a  canopy  of  foliage 
or  are  disguised  with  paint. 

The  huge  guns  recently  built  to  defend  our 
coasts  are  intended  to  fire  a  shell  that  will  pierce 
the  heavy  armor  of  a  modern  dreadnought. 
The  shell  is  arranged  to  explode  after  it  has 
penetrated  the  armor,  and  the  penetrating- 
power  is  a  very  important  matter.  About 
thirty  years  ago  the  British  built  three  battle- 
ships, each  fitted  with  two  guns  of  1614-inch  cali- 
ber and  30-caliber  length.  In  order  to  test  the 
penetrating-power  of  this  gun  a  target  was 


GUNS  AND  SUPER-GUNS  79 

built,  consisting  first  of  twenty  inches  of  steel 
armor  and  eight  inches  of  wrought-iron ;  this 
was  backed  by  twenty  feet  of  oak,  five  feet  of 
granite,  eleven  feet  of  concrete,  and  six  feet 
of  brick.  When  the  shell  struck  this  target  it 
passed  through  the  steel,  the  iron,  the  oak,  the 
granite,  and  the  concrete,  and  did  not  stop  until 
it  had  penetrated  three  feet  of  the  brick.  We 
have  not  subjected  our  16-inch  gun  to  such  a 
test,  but  we  know  that  it  would  go  through  two 
such  targets  and  still  have  plenty  of  energy  left. 
Incidentally,  it  costs  us  $1,680  each  time  the  big 
gun  is  -fired. 

THE    FAMOUS    FORTY-TWO-CENTIMETER    GUN 

One  of  the  early  surprises  of  the  war  was  the 
huge  gun  used  by  the  Germans  to  destroy  the 
powerful  Belgian  forts.  Properly  speaking, 
this  was  not  a  gun,  but  a  howitzer;  and  right 
here  we  must  learn  the  difference  between  mor- 
tars, howitzers,  and  guns.  What  we  usually 
mean  by  "gun"  is  a  piece  of  long  caliber  which 
is  designed  to  hurl  its  shell  with  a  flat  trajec- 
tory. But  long  ago  it  was  found  advantageous 
to  throw  a  projectile  not  at  but  upon  a  fortifica- 
tion, and  for  this  purpose  short  pieces  of  large 


80      INVENTIONS  OP  THE  GREAT  WAR 

bore  were  built.  These  would  fire  at  a  high 
angle,  so  that  the  projectile  would  fall  almost 
vertically  on  the  target. 

As  we  have  said,  the  bore  of  a  gun  is  rifled; 
that  is,  it  is  provided  with  spiral  grooves  that 
will  set  the  shell  spinning,  so  as  to  keep  its 
nose  pointing  in  the  direction  of  its  flight. 
Mortars,  on  the  other  hand,  were  originally  in- 
tended for  short-range  firing,  and  their  bore 
was  not  rifled.  In  recent  years,  however,  mor- 
tars have  been  made  longer  and  with  rifled 
bores,  so  as  to  increase  their  range,  and  such 
long  mortars  are  called  ' '  howitzers. ' '  The  Ger- 
man 42-centimeter  howitzer  fired  a  shell  that  was 
2,108  pounds  in  weight  and  was  about  1%  yards 
long.  The  diameter  of  the  shell  was  42  centi- 
meters, which  is  about  16%  inches.  It  carried 
an  enormous  amount  of  high  explosive,  which 
was  designed  to  go  off  after  the  shell  had 
penetrated  its  target.  The  marvel  of  this  how- 
itzer was  not  that  it  could  fire  so  big  a  shell  but 
that  so  large  a  piece  of  artillery  could  be  trans- 
ported over  the  highroads  and  be  set  for  use  in 
battle.  But  although  the  42-centimeter  gun  was 
widely  advertised,  the  real  work  of  smashing 
the  Belgian  forts  was  done  by  the  Austrian 


GUNS  AND  SUPER-GUNS  81 

"Skoda"  howitzers,  which  fired  a  shell  of  30.5- 
centimeter  (12-inch)  caliber,  and  not  by  the  42- 
centimeter  gun.  The  Skoda  howitzer  could  be 
taken  apart  and  transported  by  three  motor- 
cars of  100  horse-power  each.  The  cars  trav- 
eled at  a  rate  of  about  twelve  miles  per  hour. 
It  is  claimed  the  gun  could  be  put  together  in 
twenty-four  minutes,  and  would  fire  at  the  rate 
of  one  shot  per  minute. 

FIELD-GUNS 

So  far,  we  have  talked  only  of  the  big  guns, 
but  in  a  modern  battle  the  field-gun  plays  a  very 
important  part.  This  fires  a  shell  that  weighs 
between  fourteen  and  eighteen  pounds  and  is 
about  three  inches  in  diameter.  The  shell  and 
the  powder  that  fires  it  are  contained  in  a  cart- 
ridge that  is  just  like  the  cartridge  of  a  shoul- 
der rifle.  These  field-pieces  are  built  to  be  fired 
rapidly.  The  French  75-millimeter  gun,  which 
is  considered  one  of  the  best,  will  fire  at  the 
rate  of  twenty  shots  per  minute,  and  its  effective 
range  is  considerably  over  three  miles.  Tbe 
French  supplied  us  with  all  75-millimeter  guns 
we  needed  in  the  war,  while  we  concentrated 
our  efforts  on  the  manufacture  of  ammunition. 


82      INVENTIONS  OF  THE  GREAT  WAR 

GUNS   THAT   FIEE    GUNS 

During  the  War  of  the  Bevolution,  cannon 
were  fired  at  short  range,  and  it  was  the  cus- 
tom to  load  them  with  grape-shot,  or  smalliron 
balls,  when  firing  against  a  charging  enemy,  be- 
cause the  grape  would  scatter  like  the  shot  of 
a  shot-gun  and  tear  a  bigger  gap  in  the  ranks  of 
the  enemy  than  would  a  single  solid  cannon-ball. 
In  modern  warfare,  guns  are  fired  from  a 
greater  distance,  so  that  there  will  be  little  dan- 
ger of  their  capture.  It  is  impossible  for  them 
to  fire  grape,  because  the  ranges  are  far  too 
great ;  besides,  it  would  be  impossible  to  aim  a 
charge  of  grape-shot  over  any  considerable  dis- 
tance, because  the  shot  would  start  spreading  as 
soon  as  they  left  the  muzzle  of  the  gun  and 
would  scatter  too  far  and  wide  to  be  of  much 
service.  But  this  difficulty  has  been  overcome 
by  the  making  of  a  shell  which  is  really  a  gun  in 
itself.  Within  this  shell  is  the  grape-shot, 
which  consists  of  two  hundred  and  fifty  half- 
inch  balls  of  lead.  The  shell  is  fired  over  the 
lines  of  the  enemy,  and  just  at  the  right  moment 
it  explodes  and  scatters  a  hail  of  leaden  balls 
over  a  fairly  wide  area. 


GUNS  AND  SUPER-GUNS  83 

It  is  not  a  simple  matter  to  time  a  shrapnel 
shell  so  that  it  will  explode  at  just  the  right  mo- 
ment. Spring-driven  clockwork  has  been  tried, 
which  would  explode  a  cap  after  the  lapse  of  a 
certain  amount  of  time ;  but  this  way  of  timing 
shells  has  not  proved  satisfactory.  Nowadays 
a  train  of  gunpowder  is  used.  When  the  shell 
is  fired,  the  shock  makes  a  cap  (see  drawing  fac- 
ing page  77)  strike  a  pin,  E,  which  ignites  the 
train  of  powder,  A.  The  head  of  the  shell  is 
made  of  two  parts,  in  each  of  which  there  is  a 
powder-fuse.  There  is  a  vent,  or  short  cut, 
leading  from  one  fuse  to  the  other,  and,  by  the 
turning  of  one  part  of  the  fuse-head  with  respect 
to  the  other,  this  short  cut  is  made  to  carry  the 
train  of  fire  from  the  upper  to  the  lower  fuse 
sooner  or  later,  according  to  the  adjustment. 
The  fire  burns  along  one  powder-train  A,  and 
then  jumps  through  the  short  cut  B  to  the  other, 
or  movable  train,  as  it  is  called,  until  it  finally 
reaches,  through  hole  C,  the  main  charge  F,  in 
the  shell.  The  movable  part  of  the  fuse-head  is 
graduated  so  that  the  fuse  may  be  set  to  explode 
the  shell  at  any  desired  distance.  In  the  fuse- 
head  there  is  also  a  detonating-pin  K,  which 
will  strike  the  primer  L  and  explode  the  shell 


84       INVENTIONS  OF  THE  GREAT  WAR 

when  the  latter  strikes  the  ground,  if  the  time- 
fuse has  failed  to  act. 

When  attacking  airplanes,  it  is  important  to 
be  able  to  follow  the  flight  of  the  shell,  so  some 
shrapnel  shell  are  provided  with  a  smoke-pro- 
ducing mixture,  which  is  set  on  fire  when  the 
shell  is  discharged,  so  as  to  produce  a  trail  of 
smoke. 

In  meeting  the  attack  of  any  enemy  at  night, 
search-light  shell  are  sometimes  used.  On  ex- 
ploding they  discharge  a  number  of  "candles," 
each  provided  with  a  tiny  parachute  that  lets 
the  candle  drop  slowly  to  the  ground.  Their 
brilliant  light  lasts  fifteen  or  twenty  minutes. 
Obviously,  ordinary  search-lights  could  not  be 
used  on  the  battle-field,  because  the  lamp  would 
at  once  be  a  target  for  enemy  batteries,  but  with 
search-light  shell  the  gun  that  fires  them  can 
remain  hidden  and  one 's  own  lines  be  shrouded 
in  darkness  while  the  enemy  lines  are  brilliantly 
illuminated. 


CHAPTEE  V 

THE  BATTLE  OF  THE  CHEMISTS 

SOME  years  ago  the  nations  of  the  world 
gathered  at  the  city  of  The  Hague,  in  Hol- 
land, to  -see  what  could  be  done  to  put  an  end  to 
war.  They  did  not  accomplish  much  in  that  di- 
rection, but  they  did  draw  up  certain  rules  of 
warfare  which  they  agreed  to  abide  by.  There 
were  some  practices  which  were  considered  too 
horrible  for  any  civilized  nation  to  indulge  in. 
Among  these  was  the  use  of  poisonous  gases, 
and  Germany  was  one  of  the  nations  that  took 
a  solemn  pledge  not  to  use  gas  in  war. 

Eighteen  years  later  the  German  Army  had 
dug  itself  into  a  line  of  trenches  reaching  from 
the  English  Channel  to  Switzerland,  and  facing 
them  in  another  line  of  trenches  were  the  armies 
of  France  and  England,  determined  to  hold  back 
the  invaders.  Neither  side  could  make  an  ad- 
vance without  frightful  loss  of  life.  But1  a 
German  scientist  came  forth  with  a  scheme  for 

85 


86       INVENTIONS  OF  THE  GREAT  WAR 

breaking  the  dead-lock.  This  was  Professor 
Nernst,  the  inventor  of  a  well-known  electric 
lamp  and  a  man  who  had  always  violently  hated 
the  British.  His  plan  was  to  drown  out  the 
British  with  a  flood  of  poisonous  gas.  To  be 
sure,  there  was  the  pledge  taken  at  The  Hague 
Conference,  but  why  should  that  stand  in  Ger- 
many's way?  What  cared  the  Germans  for 
promises  now?  Already  they  had  broken  a 
pledge  in  their  violation  of  Belgium.  Already 
they  had  rained  explosives  from  the  sky  on  un- 
fortified British  cities  (thus  violating  another 
pledge  of  The  Hague  Conference) ;  already  they 
had  determined  to  war  on  defenseless  merchant- 
men. To  them  promises  meant  nothing,  if  such 
promises  interfered  with  the  success  of  German 
arms.  They  led  the  world  in  the  field  of  chem- 
istry ;  why,  they  reasoned,  should  n't  they  make 
use  of  this  advantage? 

POURING   GAS   LIKE   WATER 

It  was  really  a  new  mode  of  warfare  that  the 
Germans  were  about  to  launch  and  it  called  for 
much  study.  In  the  first  place,  they  had  to  de- 
cide what  sort  of  gas  to  use.  It  must  be  a  gas 
that  could  be  obtained  in  large  quantities.  It 


THE  BATTLE  OF  THE  CHEMISTS        87 

must  be  a  very  poisonous  gas,  that  would  act 
quickly  on  the  enemy;  it  must  be  easily  com- 
pressed and  liquefied  so  that  it  could  be  carried 
in  containers  that  were  not  too  bulky;  it  must 
vaporize  when  the  pressure  was  released;  and 
it  must  be  heavier  than  air,  so  that  it  would  not 
be  diluted  by  the  atmosphere  but  would  hug  the 
ground.  You  can  pour  gas  just  as  you  pour 
water,  if  it  is  heavier  than  air.  A  heavy  gas 
will  stay  in  the  bottom  of  an  unstoppered  bottle 
and  can  be  poured  from  one  bottle  into  another 
like  water.  If  the  gas  is  colored,  you  can  see 
it  flowing  just  as  if  it  were  a  liquid.  On  the 
other  hand,  a  gas  which  is  much  lighter  than 
air  can  also  be  kept  in  unstoppered  bottles  if 
the  bottles  are  turned  upside  down,  and  the  gas 
can  be  poured  from  one  bottle  into  another ;  but 
it  flows  up  instead  of  down. 

Chlorine  gas  was  selected  because  it  seemed 
to  meet  all  requirements.  For  the  gas  attack 
a  point  was  chosen  where  the  ground  sloped 
gently  toward  the  opposing  lines,  so  that  the 
gas  would  actually  flow  down  hill  into  them. 
Preparations  were  carried  out  with  the  utmost 
secrecy.  Just  under  the  parapet  of  the  trenches 
deep  pits  were  dug,  about  a  yard  apart  on  a 


88       INVENTIONS  OF  THE  GREAT  WAR 

front  of  fifteen  miles,  or  over  twenty-five  thou- 
sand pits.  In  these  pits  were  placed  the  chlo- 
rine tanks,  each  weighing  about  ninety  pounds. 
Each  pit  was  then  closed  with  a  plank  and  this 
was  covered  with  a  quilt  filled  with  peat  moss 
soaked  in  potash,  so  that  in  case  of  any  leakage 
the  chlorine  would  be  taken  up  by  the  potash 
and  rendered  harmless.  Over  the  quilts  sand- 
bags were  piled  to  a  considerable  height,  to 
protect  the  tanks  from  shell-fragments. 

Liquid  chlorine  will  boil  even  in  a  tempera- 
ture of  28  degrees  below  zero  Fahrenheit,  but 
in  tanks  it  cannot  boil  because  there  is  no  room 
for  it  to  turn  into  a  gas.  Upon  release  of  the 
pressure  at  ordinary  temperatures,  the  liquid 
boils  violently  and  big  clouds  of  gas  are  pro- 
duced. If  the  gas  were  tapped  off  from  the  top 
of  the  cylinder,  it  would  freeze  on  pouring  out, 
because  any  liquid  that  turns  into  a  gas  has  to 
draw  heat  from  its  surroundings.  The  greater 
the  expansion,  the  more  heat  the  gas  absorbs, 
and  in  the  case  of  the  chlorine  tanks,  had  the 
nozzles  been  set  in  the  top  of  the  tank  they 
would  very  quickly  have  been  crusted  with  frost 
and  choked,  stopping  the  flow. 

But  the  Germans  had  anticipated  this  diffi- 


THE  BATTLE  OF  THE  CHEMISTS        89 

culty,  and  instead  of  drawing  off  the  gas  from 
tfre  top  of  the  tank,  they  drew  off  the  liquid 
from  the  bottom  in  small  leaden  tubes  which 
passed  up  through  the  liquid  in  the  tank  and 
were  kept  as  warm  as  the  surrounding  liquid. 
In  fact,  it  was  not  gas  from  the  top  of  the  tank, 
but  liquid  from  the  bottom,  that  was  streamed 
out  and  this  did  not  turn  into  gas  until  it  had 
left  the  nozzle. 

WAITING   FOB   THE    WIND 

Everything  was  ready  for  the  attack  on  the 
British  in  April,  1915.  A  point  had  been  chosen 
where  the  British  lines  made  a  juncture  with 
the  French.  The  Germans  reckoned  that  a 
joint  of  this  sort  in  the  opponent's  lines  would 
be  a  spot  of  weakness.  Also,  they  had  very 
craftily  picked  out  this  particular  spot  because 
the  French  portion  of  the  line  was  manned  by 
Turcos,  or  Algerians,  who  would  be  likely  to 
think  there  was  something  supernatural  about 
a  death-dealing  cloud.  On  the  left  of  the  Afri- 
cans was  a  division  of  Canadians,  but  the  main 
brunt  of  the-  gas  was  designed  to  fall  upon  the 
Turcos.  Several  times  the  attack  was  about 
to  be  made,  but  was  abandoned  because  the 


90       INVENTIONS  OF  THE  GREAT  WAR 

wind  was  not  just  right.  The  Germans  wished 
to  pick  out  a  time  when  the  breeze  was  blowing 
steadily — not  so  fast  as  to  scatter  the  gas,  but 
yet  so  fast  that  it  would  overtake  men  who  at- 
tempted to  run  away  from  it.  It  was  not  until 
April  22  that  conditions  were  ideal,  and  then 
the  new  mode  of  warfare  was  launched. 

Just  as  had  been  expected,  the  Turcos  were 
awe-struck  when  they  saw,  coming  out  of  the 
German  trenches,  volumes  of  greenish-yellow 
gas,  which  rolled  toward  them,  pouring  down 
into  shell-holes  and  flowing  over  into  the 
trenches  as  if  it  were  a  liquid.  They  were 
seized  with  superstitious  fear,  particularly  when 
the  gas  overcame  numbers  of  them,  stifling 
them  and  leaving  them  gasping  for  breath.  Im- 
mediately there  was  a  panic  and  they  raced 
back,  striving  to  out-speed  the  pursuing 
cloud. 

For  a  stretch  of  fifteen  miles  the  Allied 
trenches  were  emptied,  and  the  Germans,  who 
followed  in  the  wake  of  the  gas,  met  with  no  op- 
position except  in  the  sector  held  by  the  Cana- 
dians. Here,  on  the  fringe  of  the  gas  cloud,  so 
determined  a  fight  was  put  up  that  the  Germans 
faltered,  and  the  brave  Canadians  held  them 


THE  BATTLE  OF  THE  CHEMISTS        91 

until  reinforcements  arrived  and  the  gap  in  the 
line  was  closed. 

The  Germans  themselves  were  new  at  the 
game  or  they  could  have  made  a  complete  suc- 
cess of  this  surprise  attack.  Had  they  made  the 
attack  on  a  broader  front,  nothing  could  have 
kept  them  from  breaking  through  to  Calais. 
The  valiant  Canadians  who  struggled  and 
fought  without  protection  in  the  stifling  clouds 
of  chlorine,  were  almost  wiped  out.  But  many 
of  them  who  were  on  the  fringe  of  the  cloud  es- 
caped by  wetting  handkerchiefs,  socks,  or  other 
pieces  of  cloth,  and  wrapping  them  around  their 
mouths  and  noses. 

The  world  was  horrified  when  it  read  of  this 
German  gas  attack,  but  there  was  no  time  to  be 
lost.  Immediately  orders  went  out  for  gas- 
masks, and  in  all  parts  of  England,  and  of 
France  as  well,  women  were  busy  sewing  the 
masks.  These  were  very  simple  affairs — 
merely  a  pad  of  cotton  soaked  in  washing-soda 
and  arranged  to  be  tied  over  the  mouth  and  nose. 
But  when  the  next  attack  came,  not  long  after 
the  first,  the  men  were  prepared  in  some  meas- 
ure for  it,  and  again  it  failed  to  bring  the  Ger- 
mans the  success  they  had  counted  upon. 


92      INVENTIONS  OF  THE  GREAT  WAR 

One  thing  that  the  Germans  had  not  counted 
upon  was  the  fact  that  the  prevailing  winds  in 
Flanders  blow  from  west  to  east.  During  the 
entire  summer  and  autumn  of  1915,  the  winds 
refused  to  favor  them,  and  no  gas  attacks  were 
staged  from  June  to  December.  This  gave  the 
British  a  long  respite  and  enabled  them  not  only 
to  prepare  better  gas-masks,  but  also  to  make 
plans  to  give  the  Hun  a  dose  of  his  own  medi- 
cine. 

WHEN  THE  WIND  PLAYED  A  TRICK  ON  THE  GERMANS 

There  were  many  disadvantages  in  the  use 
of  gas  clouds,  which  developed  as  the  Germans 
gathered  experience.  The  gas  started  from 
their  own  lines  in  a  very  dense  cloud,  but  the 
cloud  grew  thinner  and  thinner  as  it  traveled 
toward  the  enemy,  and  lost  a  great  deal  of  its 
strength.  If  the  wind  were  higher  than  fifteen 
miles  an  hour,  it  would  swirl  the  gas  around  and 
dissipate  it  before  it  did  much  harm  to  the  op- 
posing fighters.  If  the  wind  were  light,  there 
were  other  dangers.  On  one  occasion  in  1916 
a  cloud  of  gas  was  released  upon  an  Irish  regi- 
ment. The  wind  was  rather  fickle.  It  carried 
the  gas  toward  the  British  trenches,  but  before 


Courtesy  of  "Scientific  American  " 

Cleaning  Up  a  Dugout  with  the  "Fire  Broom 


THE  BATTLE  OF  THE  CHEMISTS        93 

reaching  them  the  cloud  hesitated,  the  wind 
veered  around,  and  soon  the  gas  began  to  pour 
back  upon  the  German  lines.  The  Germans 
were  entirely  unprepared  for  this  boomerang 
attack.  Many  of  the  Huns  had  no  gas-masks 
on,  and  those  who  had,  found  that  the  masks 
were  not  in  proper  working-order.  As  a  result 
of  this  whim  of  the  winds,  eleven  thousand  Ger- 
mans were  killed. 

While  chlorine  was  the  first  gas  used,  it  was 
evident  that  it  was  not  the  only  one  that  could 
be  employed.  British  chemists  had  suspected 
that  the  Germans  would  use  phosgene,  which 
was  a  much  more  deadly  gas,  and  in  the  long  in- 
terval between  June  and  December,  1915,  masks 
were  constructed  which  would  keep  out  not  only 
the  fumes  of  chlorine  but  also  the  more  poison- 
ous phosgene.  In  one  of  their  sorties  the  Brit- 
ish succeeded  in  capturing  some  valuable  notes 
on  gas  attacks,  belonging  to  a  German  general, 
which  showed  that  the  Germans  were  actually 
preparing  to  use  phosgene.  This  deadly  gas  is 
more  insidious  in  its  action  than  chlorine.  The 
man  who  inhales  phosgene  may  not  know  that 
he  is  gassed.  He  may  experience  no  ill  effects, 
but  hours  afterward,  particularly  if  he  has  ex- 


94      INVENTIONS  OF  THE  GREAT  WAR 

ercised  in  the  meantime,  he  may  suddenly  fall 
dead,  owing  to  its  paralyzing  action  on  the  heart. 

FREEING   THE   BKITISH   TRENCHES   OF   RATS 

Phosgene  was  not  used  alone,  but  had  to  be 
mixed  with  chlorine,  and  the  deadly  combina- 
tion of  the  two  destroyed  all  life  for  miles  be- 
hind the  trenches.  However,  the  British  were 
ready  for  it.  They  had  been  drilled  to  put  on 
their  masks  in  a  few  seconds'  time,  on  the  first 
warning  of  a  gas  attack.  When  the  clouds  of 
chlorine  and  phosgene  came  over  No  Man's 
Land,  they  were  prepared,  and,  except  for  cas- 
ualties among  men  whose  masks  proved  defec- 
tive, the  soldiers  in  the  trenches  came  through 
with  very  few  losses.  .All  animal  life,  however, 
was  destroyed.  This  was  a  blessing  to  the  Brit- 
ish Tommy,  whose  trenches  had  been  overrun 
with  rats)  The  British  had  tried  every  known 
method  to  get  rid  of  these  pests,  and  now,  thanks 
to  the  Germans,  their  quarters  were  most  effec- 
tively fumigated  with  phosgene  and  every  rat 
was  killed.  If  only  the  "cooties"  could  have 
been  destroyed  in  the  same  way,  the  Germans 
might  have  been  forgiven  many  of  their  offenses. 

The  disadvantages  in  the  use  of  gas  clouds 


THE  BATTLE  OF  THE  CHEMISTS        95 

became  increasingly  apparent.  What  was 
wanted  was  some  method  of  placing  the  gas 
among  the  opponents  in  concentrated  form, 
without  wasting  any  of  it  on  its  way  across  from 
one  line  to  the  other.  This  led  to  the  use  of 
shell  filled  with  materials  which  would  produce 
gas.  There  were  many  advantages  in  these 
shell.  They  could  be  thrown  exactly  where  it 
was  desired  that  they  should  fall,  without  the 
help  of  the  fickle  winds.  When  the  shell  landed 
and  burst,  the  full  effect  of  its  contents  was 
expended  upon  the  enemy.  A  gas  cloud  would 
rise  over  a  wood,  but  with  shell  the  wood  could 
be  filled  with  gas,  which,  once  there,  would  lurk 
among  the  trees  for  days.  Chemicals  could  be 
used  in  shell  which  could  not  be  used  in  a  cloud 
attack.  The  shell  could  be  filled  with  a  liquid, 
or  even  with  a  solid,  because  when  it  burst  the 
filling  would  be  minutely  pulverized.  And  so 
German  chemists  were  set  to  work  devising  all 
sorts  of  fiendish  schemes  for  poisoning,  chok- 
ing, or  merely  annoying  their  opponents. 

GAS   THAT    MADE   ONE    WEEP 

One  of  the  novel  shell  the  Germans  used  was 
known  as  the  "tear-gas"  shell.     This  was  filled 


96       INVENTIONS  OF  THE  GREAT  WAR 

with  a  liquid,  Hie  vapor  of  which  was  very  irri- 
tating to  the  eyes.  The  liquid  vaporized  very 
slowly  and  so  its  effect  would  last  a  long  time. 
However,  the  vapor  did  not  permanently  injure 
the  eyes ;  it  merely  filled  them  with  tears  to  such 
an  extent  that  a  soldier  was  unable  to  see  and 
consequently  was  confused  and  retarded  in  his 
work.  The  ' '  tear-gas ' '  shell  were  marked  with 
a  "T"  by  the  Germans  and  were  known  as 
"T-shell." 

Another  type  of  shell,  known  as  the 
"K-shell,"  contained  a  very  poisonous  liquid, 
the  object  of  which  was  to  destroy  the  enemy 
quickly.  The  effect  of  this  shell  was  felt  at 
once,  but  it  left  no  slow  vapors  on  the  ground, 
and  so  it  could  be  followed  up  almost  immedi- 
ately by  an  attack.  Later  on,  the  Germans  de- 
veloped three  types  of  gas  shell — one  known  as 
the  " Green  Cross, "  another  as  the  "Yellow 
Cross,"  and  the  third  as  the  "Blue  Cross.'7 
The  Green  Cross  shell  was  filled  with  diphos- 
gene,  or  a  particularly  dangerous  combination 
of  phosgene  in  liquid  form,  which  would  remain 
in  pools  on  the  ground  or  soak  into  the  ground 
and  would  vaporize  when  it  became  warm.  Its 
vapors  were  deadly.  One  had  always  to  be  on 


THE  BATTLE  OF  THE  CHEMISTS        97 

his  guard  against  them.  In  the  morning,  when 
the  sun  warmed  the  earth  and  vapors  were  seen 
to  rise  from  the  damp  soil,  tests  were  made  of 
the  vapors  to  see  whether  it  was  mere  water 
vapor  or  diphosgene,  before  men  were  allowed 
to  walk  through  it. 

These  vapors  were  heavier  than  air  and  would 
flow  down  into  a  trench,  filling  every  nook  and 
cranny.  If  phosgene  entered  a  trench  by  a  di- 
rect hit,  the  liquid  would  remain  there  for  days, 
rendering  that  part  of  the  trench  uninhabitable 
except  by  men  in  gas-masks.  The  infected  part 
of  the  trench,  however,  was  cut  off  from  the 
rest  of  the  trench  by  means  of  gas-locks.  In 
other  words,  blankets  were  used  to  keep  the  gas 
out,  and  usually  two  blankets  were  hung  so  that 
a  man  in  passing  from  one  part  of  the  trench 
to  another  could  lift  up  the  first  blanket,  pass 
under  it,  and  close  it  carefully  behind  him  be- 
fore opening  the  second  blanket  which  led  into 
the  portion  of  the  trench  that  was  not  infected. 

The  Germans  had  all  sorts  of  fiendish  schemes 
for  increasing  the  discomfort  of  the  Allies. 
For  instance,  to  some  of  their  diphosgene  Shell 
they  added  a  gas  which  caused  intense  vomit- 
ing. 


98      INVENTIONS  OF  THE  GREAT  WAR 

The  Yellow  Cross  shell  was  another  fiendish 
invention  of  the  Huns.  It  was  popularly  known 
as  "mustard  gas"  and  was  intended  not  to 
kill  but  merely  to  discomfort  the  enemy.  The 
gas  had  a  peculiar  penetrating  smell,  some- 
thing like  garlic,  -and  its  fumes  would  burn  the 
flesh  wherever  it  was  exposed  to  them,  produc- 
ing great  blisters  and  sores  that  were  most 
distressing.  The  material  in  the  shell  was  a 
liquid  which  was  very  hard  to  get  rid  of  because 
it  would  vaporize  so  slowly.  On  account  of  the 
persistence  of  this  vapor,  lasting  as  it  did  for 
days,  these  gas  shell  were  usually  not  fired 
by  the  Germans  on  lines  that  they  expected  to 
attack  immediately. 

THE   SNEEZING-SHELL 

The  Blue  Cross  shell  was  comparatively 
harmless,  although  very  annoying.  It  con- 
tained a  solid  which  was  atomized  by  the  ex- 
plosion of  the  shell,  and  which,  after  it  got 
into  the  nostrils,  caused  a  violent  sneezing. 
The  material,  however,  was  not  poisonous  and 
did  not  produce  any  casualties  to  speak  of, 
although  it  was  most  unpleasant.  A  storm  of 
Blue  Cross  shell  could  be  followed  almost  im- 


THE  BATTLE  OF  THE  CHEMISTS        99 

mediately  by  an  attack,  because  the  effect  of 
the  shell  would  have  been  dissipated  before 
the  attackers  reached  the  enemy  who  were  still 
suffering  from  the  irritation  of  their  nostrils. 

GAS-MASKS 

As  the  different  kinds  of  gas  shell  were  de- 
veloped, the  gas-masks  were  improved  to  meet 
them.  In  every  attack  there  were  "duds"  or 
unexploded  shell,  which  the  chemists  of  the 
Allies  analyzed.  Also,  they  were  constantly 
experimenting  with  new  gases,  themselves,  and 
often  could  anticipate  the  Germans.  The  Allies 
were  better  able  to  protect  themselves  against 
gas  attacks  than  the  Germans,  because 
there  was  a  scarcity  of  rubber  in  Germany 
for  the  manufacture  of  masks.  When  it  was 
found  that  phosgene  was  going  to  be  used,  the 
simple  cotton-wad  masks  had  to  give  way  to 
more  elaborate  affairs  with  chemicals  that 
would  neutralize  this  deadly  gas.  And  later 
when  the  mustard  gas  was  used  which  attacked 
the  eyes,  and  the  sneezing-gas  that  attacked  the 
nose,  it  was  found  necessary  to  cover  the  face 
completely,  particularly  the  eyes;  and  so  hel- 
mets of  rubber  were  constructed  which  were 


100      INVENTIONS  OF  THE  GREAT  WAR 

tightly  fitted  around  the  neck  under  the  coat 
collar.  The  inhaled  aid  was  purified  by  pas- 
sage through  a  box  or  can  filled  with  chemicals 
and  charcoal  made  of  various  materials,  such  as 
cocoanut  shells,  peach  pits,  horse-chestnuts,  and 
the  like.  Because  the  Germans  had  no  rubber 
to  spare,  they  were  obliged  to  use  leather,  which 
made  their  masks  stiff  and  heavy. 

GLASS   THAT   WILL  NOT   SHATTER 

One  of  the  greatest  difficulties  that  had  to  be 
contended  with  was  the  covering  of  the  eyes. 
There  was  danger  in  the  use  of  glass,  because 
it  was  liable  to  be  cracked  or  broken,  letting  in 
the  deadly  fumes  and  gassing  the  wearer.  Ex- 
periments were  made  with  celluloid  and  similar 
materials,  but  the  finest  gas-masks  produced 
in  the  war  were  those  made  for  our  own  soldiers, 
.in  which  the  goggles  were  of  glass,  built  up  in 
layers,  with  a  celluloid-like  material  between, 
which  makes  a  tough  composition  that  will 
stand  up  against  a  very  hard  blow.  Even  if 
it  cracks,  this  glass  will  not  shatter. 

The  glasses  were  apt  to  become  coated  on 
the  inside  with  moisture  coming  from  the  per- 
spiration of  the  face,  and  some  means  had  to  be 


THE  BATTLE  OF  THE  CHE-MISTS    *  Ifcl 

provided  for  wiping  them  off.  The  French  hit 
upon  a  clever  scheme  of  having  the  inhaled  air 
strike  the  glasses  in  a  jet  which  would  dry  off 
the  moisture  and  keep  the  glasses  clear.  Be- 
fore this  was  done,  the  masks  were  provided 
with  little  sponges  on  the  end  of  a  finger-piece, 
with  which  the  glasses  could  be  wiped  dry  with- 
out taking  the  masks  off. 

But  all  this  time,  the  Allies  were  not  merely 
standing  on  the  defensive.  No  sooner  had  the 
Germans  launched  their  first  attack  than  the 
British  and  French  chemists  began  to  pay  back 
the  Hun  in  kind.  More  attention  was  paid  to 
the  shell  than  the  cloud  attack,  and  soon  gas 
shell  began  to  rain  upon  the  Germans.  Not 
only  were  the  German  shell  copied,  but  new 
gases  were  tried.  Gas  shell  were  manufac- 
tured in  immense  quantities. 

Then  America  took  a  hand  in  the  war  and 
our  chemists  added  their  help,  while  our  fac- 
tories turned  out  steady  streams  of  shell.  If 
Germany  wanted  gas  warfare,  the  Allies  were 
determined  that  she  should  have  it.  Our  chem- 
ists were  not  afraid  to  be  pitted  against  the 
German  chemists  and  the  factories  of  the  Allies 
were  more  than  a  match  for  those  of  the  Cen- 


,102  ,  .INY^XTIONS  OF  THE  GREAT  WAR 

tral  Powers.  When  the  Germans  first  started 
the  use  of  gas,  apparently  they  counted  only 
their  own  success,  which  they  thought  would 
be  immediate  and  overwhelming.  They  soon 
learned  that  they  must  take  what  they  gave. 
The  Allies  set  them  a  pace  that  they  could  not 
keep  up  with. 

When  the  armistice  brought  the  war  to  a 
sudden  stop,  the  United  States  alone  was  mak- 
ing each  day  two  tons  of  gas  for  every  mile  of 
the  western  front.  If  the  war  had  continued, 
the  Germans  would  have  been  simply  deluged. 
As  it  was,  they  were  getting  far  more  gas  than 
they  could  possibly  produce  in  their  own  fac- 
tories and  they  had  plenty  of  reason  to  regret 
their  rash  disregard  of  their  contract  at  The 
Hague  Conference.  One  gas  we  were  making 
was  of  the  same  order  as  mustard  gas  but  far 
more  volatile,  and  had  we  had  a  chance  to  use 
it  against  the  Germans  they  would  have  found 
it  very  difficult  to  protect  themselves  against  its 
penetrating  fumes. 

BATTLING   WITH   LIQUID   FIBE 

Somewhat  associated  with  gas  warfare  was 
another  form  of  offensive  which  was  introduced 


THE  BATTLE  OF  THE  CHEMISTS      103 

with  the  purpose  of  breaking  up  the  dead-lock 
of  trench  warfare.  A  man  could  protect  him- 
self against  gas  by  using  a  suitable  mask  and 
clothing,  but  what  could  he  do  against  fire! 
It  looked  as  if  trench  defenders  would  have  to 
give  up  if  attacked  with  fire,  and  so,  early  in  the 
war,  the  Germans  devised  apparatus  for  shoot- 
ing forth  streams  of  liquid  fire,  and  the  Allies 
were  not  slow  to  copy  the  idea. 

The  apparatus  was  either  fixed  or  portable, 
but  it  was  not  often  that  the  fixed  apparatus 
could  be  used  to  advantage,  because  at  best  the 
range  of  the  flame-thrower  was  limited  and  in 
few  places  were  the  trenches  near  enough  for 
flaming  oil  to  be  thrown  across  the  intervening 
gap.  For  this  reason  portable  apparatus  was 
chiefly  used,  with  which  a  man  could  send  out  a 
stream  for  from  a  hundred  to  a  hundred  and 
fifty  feet.  On  his  back  he  carried  the  oil-tank, 
in  the  upper  part  of  which  there  was  a  charge 
of  compressed  air..  A  pipe  led  from  the  tank 
to  a  nozzle  which  the  man  held  in  his  hand, 
using  it  to  direct  the  spray. 

There  was  some  danger  to  the  operator  in 
handling  a  highly  inflammable  oil.  The  blaze 
might  flare  back  and  burn  him,  particularly 


104      INVENTIONS  OF  THE  GREAT  WAR 

when  he  was  lighting  the  stream,  and  so  a 
special  way  of  setting  fire  to  the  spray  had  to  be 
devised.  Of  course,  the  value  of  the  apparatus 
lay  in  its  power  to  shoot  the  stream  as  far  as 
possible.  The  compressed  air  would  sent  the 
stream  to  a  good  distance,  but  after  lighting, 
the  oil  might  be  consumed  before  it  reached  the 
desired  range.  Some  way  had  to  be  found  of 
igniting  the  oil  stream  far  from  the  nozzle  or 
as  near  the  limit  of  its  range  as  possible.  And 
so  two  nozzles  were  used,  one  with  a  small  open- 
ing so  that  it  would  send  out  a  fine  jet  of  long 
range,  while  the  main  stream  of  oil  issued  from 
the  second  nozzle.  The  first  nozzle  was  mov- 
able with  respect  to  the  second  and  the  two 
streams  could  be  regulated  to  come  together  at 
any  desired  distance  from  the  operator  within 
the  range  of  the  apparatus.  The  fine  stream 
was  ignited  and  carried  the  flame  out  to  the 
main  stream,  setting  fire  to  it  near  the  limit  of 
its  range.  In  this  way  a  flare-back  was  avoided 
and  the  oil  blazed  where  the  flame  was  needed. 
The  same  sort  of  double  nozzle  was  used  on  the 
stationary  apparatus  and  because  weight  was 
not  a  consideration,  heavier  apparatus  was  used 
which  shot  the  stream  to  a  greater  distance. 


THE  BATTLE  OF  THE  CHEMISTS      105 

But  flame-throwing  apparatus  had  its  draw- 
backs: there  was  always  the  danger  that  the 
tank  of  highly  inflammable  oil  might  be  burst 
open  by  a  shell  or  hand-grenade  and  its  con- 
tents set  on  fire.  The  fixed  apparatus  was 
buried  under  bags  of  sand,  but  the  man  who 
carried  flame-throwing  apparatus  on  his  back 
had  to  take  his  chances,  not  knowing  at  what 
instant  the  oil  he  carried  might  be  set  ablaze, 
turning  him  into  a  living,  writhing,  human 
torch.  Because  of  this  hazard,  liquid  fire  did 
not  play  a  very  important  part  in  trench  war- 
fare; to  set  fire  to  the  spray  at  its  source  with 
a  well  directed  hand-grenade  was  too  easy. 


There  were  certain  situations,  however,  in 
which  liquid  fire  played  a  very  important  part. 
After  a  line  of  trenches  had  been  captured  it 
was  difficult  to  clear  out  the  enemy  who  lurked 
in  dugouts  and  underground  passages.  They 
would  not  surrender,  and  from  their  hidden 
recesses  they  could  pour  out  a  deadly  machine- 
gun  fire.  The  only  way  of  dislodging  them 
was  to  use  the  "fire  broom. "  In  other  words, 
a  stream  of  liquid  fire  was  poured  into  the  dug- 


106      INVENTIONS  OF  THE  GREAT  WAR 

out,  burning  out  the  men  trapped  in  it.  If 
there  were  a  second  exit,  they  would  come  tum- 
bling out  in  a  hurry.  If  not,  they  would  be 
burned  to  death.  After  the  first  sweep  of  the 
"  broom, "  if  there  were  any  survivors,  there 
would  not  be  any  fight  left  in  them,  and  they 
would  be  quick  to  surrender  before  being  sub- 
jected to  a  second  dose  of  fire. 


CHAPTEE  VI 
TANKS 

r  1 1  HEBE  is  no  race-horse  that  can  keep  up 
A  with  an  automobile,  no  deer  that  can  out- 
run a  locomotive.  A  bicyclist  can  soon  tire  out 
the  hardiest  of  hounds.  Why?  Because  ani- 
mals run  on  legs,  while  machines  run  on  wheels. 

As  wheels  are  so  much  more  speedy  than  legs, 
it  seems  odd  that  we  do  not  find  this  form  of 
locomotion  in  nature.  There  are  many  animals 
that  owe  their  very  existence  to  the  fact  that 
they  can  run  fast.  Why  hasn't  nature  put 
them  on  wheels  so  that  when  their  enemy  ap- 
pears they  can  roll  away,  sedately,  instead  of 
having  to  jerk  their  legs  frantically  back  and 
forth  at  the  rate  of  a  hundred  strokes  a  minute  I 

But  one  thing  we  must  not  overlook.  Our 
wheeled  machines  must  have  a  special  road 
prepared  for  them,  either  a  macadam  highway 
or  a  steel  track.  They  are  absolutely  helpless 

107 


108      INVENTIONS  OF  THE  GREAT  WAR 

when  they  are  obliged  to  travel  over  rough 
country.  No  wheeled  vehicle  can  run  through 
fields  broken  by  ditches  and  swampy  spots,  or 
over  ground  obstructed  with  boulders  and  tree- 
stumps. 

But  it  is  not  always  possible  or  practicable 
to  build  a  road  for  the  machines  to  travel  upon, 
and  it  is  necessary  to  have  some  sort  of  self- 
propelled  vehicle  that  can  travel  over  all  kinds 
of  ground. 

Some  time  ago  a  British  inventor  developed 
a  machine  with  large  wheels  on  which  were 
mounted  the  equivalent  of  feet.  As  the  wheels 
revolved,  these  feet  would  be  planted  firmly  on 
the  ground,  one  after  the  other,  and  the  machine 
would  proceed  step  by  step.  It  could  travel 
over  comparatively  rough  ground,  and  could 
actually  walk  up  a  flight  of  stairs.  We  have  a 
very  curious  walking-machine  in  this  country. 
It  is  a  big  dredge  provided  with  two  broad 
feet  and  a  "swivel  chair. "  The  machine 
makes  progress  by  alternately  planting  its  feet 
on  the  ground,  lifting  itself  up,  chair  and  all, 
pushing  itself  forward,  and  sitting  down  again. 

Although  many  other  types  of  walking-ma- 
chines have  been  patented,  none  of  them  has 


TANKS  109 

amounted  to  very  much.  Clearly,  nature  hope- 
lessly outclasses  us  in  this  form  of  propulsion. 

Years  ago  it  occured  to  one  ingenious  man 
that  if  wheeled  machines  must  have  tracks  or 
roads  for  their  wheels  to  run  on,  they  might  be 
allowed  to  lay  their  own  tracks.  And  so  he 
arranged  his  track  in  the  form  of  an  endless 
chain  of  plates  that  ran  around  the  wheels  of 
his  machine.  The  wheels  merely  rolled  on  this 
chain,  and  as  they  progressed,  new  links  of  the 
track  were  laid  down  before  them  and  the  links 
they  had  passed  over  were  picked  up  behind 
them.  A  number  of  inventors  worked  on  this 
idea,  but  one  man  in  particular,  Benjamin  Holt, 
of  Peoria,  Illinois,  brought  the  invention  to  a 
high  state  of  perfection.  He  arranged  a  series 
of  wheels  along  the  chain  track,  each  carrying 
a  share  of  the  load  of  the  machine,  and  each 
mounted  on  springs  so  that  it  would  yield  to 
any  unevenness  of  the  ground,  just  as  a  cater- 
pillar conforms  itself  to  the  hills  and  dales  of 
the  surface  it  creeps  over.  In  fact,  the  ma- 
chine was  called  a  "  caterpillar "  tractor  be- 
cause of  its  crawling  locomotion. 

But  it  was  no  worm  of  a  machine.  In  power 
it  was  a  very  elephant.  It  could  haul  loads 


110      INVENTIONS  OF  THE  GREAT  WAR 

that  would  tax  the  strength  of  scores  of  horses. 
Stumps  and  boulders  were  no  obstacles  in  its 
path.  Even  ditches  could  not  bar  its  progress. 
The  machine  would  waddle  down  one  bank 
and  up  the  other  without  the  slightest  diffi- 
culty. It  was  easily  steered;  in  fact,  it  could 
turn  around  in  its  own  length  by  traveling  for- 
ward on  one  of  its  chains,  or  traction-belts, 
and  backward  on  the  other.  The  machine  was 
particularly  adapted  to  travel  on  soft  or  plowed 
ground,  because  the  broad  traction-belts  gave 
it  a  very  wide  bearing  and  spread  its  weight 
over  a  large  surface.  It  was  set  to  work  on 
large  farms,  hauling  gangs  of  plows  and  culti- 
vators. Little  did  Mr.  Holt  think,  as  he 
watched  his  powerful  mechanical  elephants  at 
work  on  the  vast  Western  wheat-fields,  that 
they,  or  rather  their  offspring,  would  some  day 
play  a  leading  role  in  a  war  that  would  rack  the 
whole  world. 

But  we  are  getting  ahead  of  our  story.  To 
start  at  the  very  beginning,  we  must  go  back 
to  the  time  when  the  first  savage  warrior  used 
a  plank  of  wood  to  protect  himself  from  the 
rocks  hurled  by  his  enemy.  This  was  the  start 


TANKS  111 

of  the  never-ending  competition  between  arms 
and  armor.  As  the  weapons  of  offense  de- 
veloped from  stone  to  spear,  to  arrow,  to  arque- 
bus, the  wooden  plank  developed  into  a  shield 
of  brass  and  then  of  steel;  and  then,  since  a 
separate  shield  became  too  bothersome  to 
carry,  it  was  converted  into  armor  that  the 
warrior  could  wear  and  so  have  both  hands  free 
for  battle.  For  every  improvement  in  arms 
there  was  a  corresponding  improvement  in 
armor. 

After  gunpowder  was  invented,  the  idea  of 
armor  for  men  began  to  wane,  because  no  armor 
could  be  built  strong  enough  to  ward  off  the 
rifle-bullet  and  at  the  same  time  light  enough 
for  a  man  to  wear.  The  struggle  between  arms 
and  armor  was  then  confined  to  the  big  guns 
and  the  steel  protection  of  forts  and  war-ships. 

But  not  so  long  ago  the  machine-gun  was  in- 
vented, and  this  introduced  a  new  phase  of  war- 
fare. Not  more  than  one  rifle-bullet  in  a  thou- 
sand finds  its  mark  on  the  battle-field.  The 
Boers  in  the  battle  of  Colenso  established  a 
record  with  one  hit  in  six  hundred  shots.  In 
the  excitement  of  battle  men  are  too  nervous  to 
take  careful  aim  and  they  are  apt  to  fire  either 


112      INVENTIONS  OF  THE  GREAT  WAR 

too  high  or  too  low,  so  that  the  mortality  is 
not  nearly  so  great  as  some  would  expect.  But 
with  the  machine-gun  there  is  not  this  waste  of 
ammunition,  because  it  fires  a  stream  of 
bullets,  the  effect  of  which  can  readily  be  deter- 
mined by  the  man  who  operates  the  volley.  The 
difference  between  the  machine-gun  fire  and 
rifle  fire  is  something  like  the  difference  between 
hitting  a  tin  can  with  a  stone  or  with  a  stream  of 
water.  It  is  no  easy  matter  to  score  a  hit  with 
the  stone;  but  any  one  can  train  a  garden  hose 
on  the  can,  because  he  can  see  where  the  water  is 
striking  and  move  his  hose  accordingly  until  he 
covers  the  desired  spot.  In  the  -same  way, 
with  the  machine-gun,  it  is  much  easier  to  train 
the  stream  of  bullets  upon  the  mark,  and,  having 
once  found  the  mark,  to  hold  the  aim.  That  is 
one  reason  why  the  destruction  of  a  machine- 
gun  is  so  tremendous ;  another,  of  course,  being 
that  it  will  discharge  so  many  more  shots  per 
minute  than  the  common  rifle. 

In  the  Eusso-Japanese  War,  the  Eussians 
played  havoc  with  the  attacking  Japanese  at 
Port  Arthur  by  using  carefully  concealed  ma- 
chine-guns, and  the  German  military  attaches 
were  quick  to  note  the  value  of  the  machine- 


(C)  Underwood  &  Underwood 

Even  Trees  were  no  Barrier  to  the  British  Tank 


Press  Illustrating  Service 

The  German  Tank  was  very  heavy  and  cumbersome 


TANKS  113 

gun.  Secretely  they  manufactured  large  num- 
bers of  machine-guns  and  established  a  special 
branch  of  service  to  handle  the  guns,  and  they 
developed  the  science  of  using  them  with  telling 
effect.  And  so,  when  the  recent  great  war  sud- 
denly broke  out,  they  surprised  the  world  with 
the  countless  number  of  machine-guns  they  pos- 
sessed and  the  efficient  use  to  which  they  put 
them.  Thousands  of  British  soldiers  in  the 
early  days  of  the  war  fell  victims  to  these  death- 
dealing  machines.  Two  or  three  men  with  a 
machine-gun  could  defy  several  companies  of 
soldiers,  especially  when  the  attackers  had  to 
cut  their  way  through  barbed-wire  entangle- 
ments. It  was  clearly  evident  that  something 
must  be  done  to  defend  the  men  against  the 
machine-gun;  for  to  charge  against  it  meant, 
simply,  wholesale  slaughter. 

At  first  the  only  means  of  combating  the  ma- 
chine-guns seemed  to  be  to  destroy  them  with 
shell-fire;  but  they  were  carefully  concealed, 
and  it  was  difficult  to  search  them  out.  Only 
by  long-continued  bombardment  was  it  possible 
to  destroy  them  and  tear  away  the  barbed  wire 
sufficiently  to  permit  of  a  charge.  Before  an 
enemy  position  was  stormed  it  was  subjected  to 


114      INTENTIONS  OF  THE  GREAT  WAR 

the  fire  of  thousands  -of  guns  of  all  calibers  for 
hours  and  even  days. 

But  this  resulted  in  notifying  the  enemy  that 
a  charge  was  ere  long  to  be  attempted  at  a 
certain  place,  and  he  could  assemble  his  reserves 
for  a  counter-attack.  Furthermore,  the  Ger- 
mans learned  to  conceal  their  machine-guns  in 
dugouts  twenty  or  thirty  feet  underground, 
where  they  were  safe  from  the  fire  of  the  big 
guns,  and  then,  when  the  fire  let  up,  the  weapons 
would  be  dragged  up  to  the  surface  in  time  to 
mow  down  the  approaching  infantry. 

It  was  very  clear  that  something  would  have 
to  be  done  to  combat  the  machine-gun.  If  the 
necessary  armor  was  too  heavy  for  the  men 
to  carry,  it  must  carry  itself.  Armored  auto- 
mobiles were  of  no  service  at  all,  because  they 
could  not  possibly  travel  over  the  shell-pitted 
ground  of  No  Man's  Land.  The  Eussians 
tried  a  big  steel  shield  mounted  on  wheels, 
which  a  squad  of  soldiers  would  push  ahead 
of  them,  but  their  plan  failed  because  the  wheels 
would  get  stuck  in  shell-holes.  A  one-man 
shield  on  wheels  was  tried  by  the  British.  Un- 
der its  shelter  a  man  could  steal  up -to  the  barbed 
wire  and  cut  it  and  even  crawl  up  to  a  machine- 


TANKS  115 

gun  emplacement  and  destroy  it  with  a  hand- 
grenade.  But  this  did  not  prove  very  success- 
ful, either,  because  the  wheels  did  not  take 
kindly  to  the  rough  ground  of  the  battle-field. 

And  here  is  where  we  come  back  to  Mr. 
Holt's  mechanical  elephants.  Just  before  the 
great  war  broke  out,  Belgium — poor  unsus- 
pecting Belgium — was  holding  an  agricultural 
exhibit.  An  American  tractor  was  on  exhi- 
bition. It  was  the  one  developed  by  Mr. 
Holt,  and  its  remarkable  performances  gained 
for  it  a  reputation  that  spread  far  and 
wide.  Colonel  E.  D.  Swinton  of  the  British 
Army  heard  of  the  peculiar  machine,  and  im- 
mediately realized  the  advantages  of  an  ar- 
mored tractor  for  battle  over  torn  ground. 
But  in  the  first  few  months  of  the  war  that 
ensued,  this  idea  was  forgotten,  until  the  ef- 
fectiveness of  the  machine-gun  and  the  neces- 
sity for  overcoming  it  recalled  the  matter 
to  his  mind.  At  his  suggestion  a  caterpillar 
tractor  was  procured,  and  the  military  engi- 
neers set  themselves  to  the  task  of  designing  an 
armored  body  to  ride  on  the  caterpillar-trac- 
tor belts,  Of  course  the  machine  had  to  be 


116     INVENTIONS  OF  THE  GREAT  WAR 

entirely  re-designed.  The  tractor  was  built  for 
hauling  loads,  and  not  to  climb  out  of  deep  shell- 
holes;  but  by  running  the  traction-belts  over 
the  entire  body  of  the  car,  and  running  the 
forward  part  of  the  tractor  up  at  a  sharp  an- 
gle the  engineers  overcame  that  difficulty. 

In  war,  absolute  secrecy  is  essential  to  the 
success  of  any  invention,  and  the  British  en- 
gineers were  determined  to  let  no  inkling  of 
the  new  armored  automobiles  reach  the  enemy. 
Different  parts  of  the  machines  were  made  in 
different  factories,  so  that  no  one  would  have 
an  idea  of  what  the  whole  would  look  like.  At 
first  the  new  machine  was  known  as  a  "  land- 
cruiser  "  or  "  land-ship  ";  but  it  was  feared  that 
this  very  name  would  give  a  clue  to  spies,  and 
so  any  descriptive  name  was  forbidden.  Many 
of  the  parts  consisted  of  rolled  steel  plates 
which  might  readily  be  used  in  building  up  ves- 
sels to  hold  water  or  gasolene ;  and  to  give  the 
impression  that  such  vessels  were  being  con- 
structed the  name  "tank"  was  adopted.  The 
necessity  of  guarding  even  the  name  of  the  ma- 
chines was  shown  later,  when  rumors  leaked 
out  that  the  tanks  were  being  built  to  carry 
water  over  the  desert  regions  of  Mesopotamia 


TANKS  117 

and  Egypt.  Another  curious  rumor  was  that 
the  machines  were  snow-plows  for  use  in  Rus- 
sia. To  give  some  semblance  of  truth  to  this 
story,  the  parts  were  carefully  labeled,  "For 
Petrograd." 

Probably  never  was  a  military  secret  so  well 
guarded  as  this  one,  and  when,  on  September 
15,  1916,  the  waddling  steel  tractors  loomed  up 
out  of  the  morning  mists,  the  German  fighters 
were  taken  completely  by  surprise.  Two  days 
before,  their  airmen  had  noticed  some  peculiar 
machines  which  they  supposed  were  armored 
automobiles.  They  had  no  idea,  however,  that 
such  formidable  monsters  were  about  to  de- 
scend upon  them. 

The  tanks  proceeded  leisurely  over  the  shell- 
torn  regions  of  No  Man's  Land,  wallowing 
down  into  shell-holes  and  clambering  up  out  of 
them  with  perfect  ease.  They  straddled  the 
trenches  and  paused  to  pour  down  them  streams 
of  machine-gun  bullets.  Wire  entanglements 
were  nothing  to  them ;  under  their  weight  steel 
wire  snapped  like  thread.  The  big  brutes 
marched  up  and  down  the  lines  of  wire,  treading 
them  down  into  the  ground  and  clearing  the  way 
for  the  infantry.  Even  trees  were  no  barrier 


118      INVENTIONS  OF  THE  GREAT  WAR 

to  these  tanks.  Of  course  they  did  not  attack 
large  ones,  but  the  smallish  trees  were  simply 
broken  down  before  their  onslaughts.  As  for 
concrete  emplacements  for  machine-guns,  the 
tanks  merely  rode  over  them  and  crushed  them. 
Those  who  attempted  to  defend  themselves  in 
the  ruins  of  buildings  found  that  the  tanks 
could  plow  right  through  walls  and  bring  them 
down  in  a  shower  of  bricks  and  stone.  There 
was  no  stopping  these  monsters,  and  the  Ger- 
mans fled  in  consternation  before  them. 

There  were  two  sizes  of  tanks.  The  larger 
ones  aimed  to  destroy  the  machine-gun  emplace- 
ments, and  they  were  fitted  up  with  guns  for  fir- 
ing a  shell.  The  smaller  tanks,  armed  with 
machine-guns,  devoted  themselves  to  fighting 
the  infantry.  British  soldiers  following  in  the 
wake  of  the  bullet-proof  tank  were  protected 
from  the  shots  of  the  enemy  and  were  ready  to 
attack  him  with  bayonets  when  the  time  was 
ripe.  But  the  tanks  also  furnished  an  indirect 
protection  for  the  troops.  It  was  not  necessary 
for  the  men  to  conceal  themselves  behind  the 
big  tractors.  Naturally,  every  Hun  who  stood 
his  ground  and  fought,  directed  all  his  fire  upon 
the  tanks,  leaving  the  British  infantry  free  to 


TANKS  119 

charge  virtually  unmolested.  The  success  of 
the  tank  was  most  pronounced. 

In  the  meantime  the  French  had  been  in- 
formed of  the  plans  of  their  allies,  and  they  set 
to  work  on  a  different  design  of  tractor.  It 
was  not  until  six  months  later  that  their  ma- 
chines saw  service.  The  French  design  dif- 
fered from  the  British  mainly  in  having  the 
tractor  belt  confined  to  the  wheels  instead  of 
running  over  the  entire  body  of  the  tank.  It 
was  more  blunt  than  the  British  and  was  pro- 
vided at  the  forward  end  with  a  steel  cutting- 
edge,  which  adapted  it  to  break  its  way  through 
wire  entanglements.  At  each  end  there  are  two 
upward-turning  skids  which  helped  the  tank 
to  lift  itself  out  of  a  hole.  The  larger  machines 
carried  a  regular  75-millimeter  (3-inch)  field- 
gun,  which  is  a  very  formidable  weapon.  They 
carried  a  crew  of  one  officer  and  seven  men. 

Life  in  a  tank  is  far  from  pleasant.  The  heat 
and  the  noise  of  machinery  and  guns  are  terrific. 
Naturally,  ventilation  is  poor  and  the  fumes  and 
gases  that  accumulate  are  most  annoying,  to 
say  the  least.  Sometimes  the  men  were  over- 
come by  them.  But  war  is  war,  and  such  dis- 
comforts had  to  be  endured, 


120      INVENTIONS  OF  THE  GREAT  WAR 

But  the  tank  possessed  one  serious  defect 
which  the  Germans  were  not  slow  to  discover. 
Its  armor  was  proof  against  machine-gun  fire, 
but  it  could  not  ward  off  the  shells  of  field- 
guns,  and  it  was  such  a  slow  traveler  that  the 
enemy  did  not  find  it  a  very  difficult  task  to 
hit  it  with  a  rapid-fire  gun  if  the  gunner  could 
see  his  target.  And  so  the  Germans  ordered  up 
their  guns  to  the  front  lines,  where  they  could 
score  direct  hits.  Only  light  guns  were  used 
for  this  purpose,  especially  those  whose  rifling 
was  warn  down  by  long  service,  because 
long  range  was  not  necessary  for  tank 
fighting. 

When  the  Germans  began  their  final  great 
drive,  it  was  rumored  that  they  had  built  some 
monster  tanks  that  were  far  more  formidable 
than  anything  the  Allies  had  produced.  Un- 
like the  British,  they  used  the  tanks  not  to  lead 
the  army  but  to  follow  and  destroy  small  nests 
of  French  and  British  that  were  left  behind. 
When  the  French  finally  did  capture  one  of  the 
German  tanks,  which  had  fallen  into  a  quarry, 
it  proved  to  be  a  poor  imitation.  It  was  an 
ugly-looking  affair,  very  heavy  and  cumber- 
some. Owing  to  the  scarcity  of  materials  for 


(C)  Underwood  &  Underwood 

The    Speedy    British    "Whippet"    Tank  that   can   travel   at   a 
speed  of  twelve  miles  per  hour 


CO  Underwood  &  Underwood 

The  French  High-Speed  "Baby"  Tank 


•sl 
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<L>    ., 
£    C 


II 


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r      rt  o 


. 


TANKS  121 

producing  high-grade  armor,  it  had  to  make 
up  in  thickness  of  plating  what  it  lacked  in 
quality  of  steel.  The  tank  was  intended  to 
carry  a  crew  of  eighteen  men  and  it  fairly 
bristled  with  guns,  but  it  could  not  manceuver 
as  well  as  the  British  tank;  for  when  some 
weeks  later  a  fleet  of  German  tanks  encountered 
a  fleet  of  heavy  British  tanks,  the  Hun  machines 
were  completely  routed. 

It  was  then  that  the  British  sprang  another 
surprise  upon  the  Germans.  After  the  big 
fellows  had  done  their  work,  a  lot  of  baby  tanks 
appeared  on  the  scene  and  chased  the  German 
infantry.  These  little  tanks  could  travel  at  a 
speed  of  twelve  miles  an  hour,  which  is  about 
as  fast  as  an  ordinary  man  can  run.  "  Whip- 
pets, "  the  British  called  them,  because  they 
were  like  the  speedy  little  dogs  of  that  name. 
They  carried  but  two  men,  one  to  guide  the  tank 
and  the  other  to  operate  the  machine-gun.  The 
French,  too,  built  a  light  ." mosquito"  tank, 
which  was  even  smaller  than  the  British  tank, 
and  fully  as  fast.  It  was  with  these  machines, 
which  could  dart  about  quickly  on  the  battle- 
field and  dodge  the  shell  of  the  field-guns,  and 
which  were  immune  to  the  fire  of  the  machine- 


122      INVENTIONS  OF  THE  GREAT  "WAR 

gun,  that  the  Allies  were  able  to  make  progress 
against  the  Germans. 

When  the  Germans  retired,  they  left  behind 
them  nests  of  machine-guns  to  cover  the  with- 
drawal of  their  armies.  These  gunners  were 
ordered  to  fight  to  the  very  end.  They  looked 
for  no  mercy  and  expected  no  help.  Had  it 
not  been  for  the  light  tanks,  it  would  have  been 
well  nigh  impossible  to  overcome  these  deter- 
mined bodies  of  men  without  frightful  losses. 

Since  America  invented  the  machine-gun  and 
also  barbed  wire,  and  since  America  furnished 
the  inspiration  for  the  tank  with  which  to  tram- 
ple down  the  wire  entanglements  and  stamp  out 
the  machine-guns,  naturally  people  expected 
our  army  to  come  out  with  something  better 
than  anything  produced  by  our  allies.  We  did 
turn  out  a  number  of  heavy  machines  patterned 
after  the  original  British  tank,  with  armor  that 
could  stand  up  against  heavy  fire,  and  we  also 
produced  a  small  and  very  speedy  tank  similar 
to  the  French  "baby"  tank,  but  before  we  could 
put  these  into  service  the  war  ended.  The 
tanks  we  did  use  so  effectively  at  St.-Mihiel 
and  in  the  Argonne  Forest  were  supplied  by 
the  French. 


CHAPTER  VII 
THE  WAB  IN  THE  AIR 

WE  Americans  are  a  peace-loving  people, 
which  is  the  very  reason  why  we  went 
into  the  war.  We  had  to  help  down  the 
power  that  was  disturbing  the  peace  of  the 
world.  We  do  not  believe  in  conquests — at 
least  of  the  type  that  Germany  tried  to  force 
— and  yet  there  are  certain  conquests  that  we 
do  indulge  in  once  in  a  while. 

Eleven  years  before  Germany  undertook  to 
conquer  Europe  two  young  Americans  made  the 
greatest  conquest  that  the  world  has  ever  seen. 
The  Wright  brothers  sailed  up  into  the  heavens 
and  gained  the  mastery  of  the  air.  They  of- 
fered their  conquest  to  the  United  States;  but 
while  we  accepted  their  offering  with  enthusi- 
asm at  first,  we  did  not  know  what  to  do  with 
the  new  realm  after  we  got  it.  There  seemed 
to  be  no  particular  use  in  flying.  It  was  just 

123 


124      INVENTIONS  OF  THE  GREAT  WAR 

a  bit  too  risky  to  be  pleasant  sport,  and  about 
all  we  could  see  in  it  was  an  exhibition  for  the 
circus  or  the  county  fair. 

Not  so  in  Europe,  however.  Flying  meant 
something  over  there — there  where  the  fron- 
tiers have  ever  bristled  with  big  guns  and 
strong  fortifications,  and  where  huge  military 
forces  have  slept  on  their  arms,  never  knowing 
what  dreadful  war  the  morning  would  bring 
forth.  The  war-lovers  hailed  the  airplane  as 
a  new  instrument  with  which  to  terrorize  their 
neighbors;  the  peace-lovers  saw  in  it  another 
menace  to  their  homes ;  it  gave  them  a  new  fron- 
tier to  defend.  And  so  the  military  powers  of 
Europe  took  up  the  airplane  seriously  and 
earnestly  and  developed  it. 

At  first  military  authorities  had  rated  the 
airplane  chiefly  as  a  flying  scout.  Some  bomb- 
dropping  experiments  had  been  made  with  it, 
but  it  proved  very  difficult  to  land  the  bombs 
near  the  target,  and,  besides,  machines  of  those 
days  were  not  built  to  carry  very  heavy  loads, 
so  that  it  did  not  seem  especially  profitable  to 
attack  the  enemy  from  the  skies.  As  for  actual 
battles  up  among  the  clouds,  they  were  dreamed 
of  only  by  the  writers  of  fiction.  But  wild 


THE  WAR  IN  THE  AIR  125 

dreams  became  stern  realities  in  the  mighty 
struggle  between  the  great  powers  of  the  world. 

EYES   IN   THE   SKY 

As  a  scouting-machine  the  airplane  did 
prove  to  be  far  superior  to  mounted  patrols 
which  used  to  perform  scout-work.  In  fact,  it 
changed  completely  the  character  of  modern 
warfare.  From  his  position  high  up  in  the 
heavens  the  flying  scout  had  an  unobstructed 
view  of  the  country  for  miles  and  he  could  see 
just  what  the  enemy  was  doing.  He  could  see 
whether  large  forces  of  men  were  collecting  for 
an  attack.  He  could  watch  the  course  of  sup- 
ply-trains, and  judge  of  their  size.  He  could 
locate  the  artillery  of  the  enemy  and  come  back 
with  information  which  in  former  times  a  scout 
posted  in  a  tall  tree  or  even  in  a  captive  balloon 
could  not  begin  to  acquire.  Surprise  attacks 
were  impossible,  with  eyes  in  the  sky.  The 
aviator  could  help  his  own  batteries  by  signal- 
ing to  them  where  to  send  their  shell,  and  when 
the  firing  began  he  would  spot  the  shots  as  they 
landed  and  signal  back  to  the  battery  how  to 
correct  its  aim  so  as  to  drop  the  shell  squarely 
on  the  target. 


126      INVENTIONS  OF  THE  GREAT  WAR 

The  French  sprang  a  surprise  on  the  Ger- 
mans by  actually  attacking  the  infantry  from 
the  sky.  The  idea  of  attack  from  overhead 
was  so  novel  that  armies  did  not  realize  the 
danger  of  exposing  themselves  behind  the  bat- 
tle-front. Long  convoys  of  trucks  and  masses 
of  infantry  moved  freely  over  the  roads 
behind  the  lines  and  they  were  taken  by  sur- 
prise when  the  French  began  dropping  steel 
darts  upon  them.  These  were  about  the  size 
of  a  pencil,  with  pointed  end  and  fluted  tail, 
so  that  they  would  travel  through  the  air  like 
an  arrow.  The  darts  were  dropped  by  the 
hundred  wherever  the  airmen  saw  a  large 
group  of  the  enemy,  and  they  struck  with  suf- 
ficient velocity  to  pierce  a  man  from  head  to 
foot.  But  steel  darts  were  not  used  very  long. 
The  enemy  took  to  cover  and  then  the  only  way 
to  attack  him  was  to  drop  explosives  which 
would  blow  up  his  shelter. 

At  the  outset,  air  scouts  were  more  afraid  of 
the  enemy  on  the  ground  than  in  the  sky.  The 
Germans  had  anti-aircraft  guns  that  were  fired 
with  accuracy  and  accounted  for  many  Allied 
planes.  In  those  days,  airplanes  flew  at  com- 
paratively low  altitudes  and  they  were  well 


THE  WAft  IN  THE  AIB  127 

within  the  reach  of  the  enemy's  guns.  But  it 
was  not  long  before  the  airplanes  began  to  fight 
one  another.  Each  side  was  very  much  an- 
noyed by  the  flying  scouts  of  its  opponents  and 
after  a  number  of  pistol  duels  in  the  sky  the 
French  began  to  arm  their  planes  with  machine- 
guns. 

Two  months  after  the  war  started  the  first 
airplane  was  sent  crashing  to  earth  after  a  bat- 
tle in  the  sky.  The  fight  took  place  five  thou- 
sand feet  above  the  earth,  between  a  French 
and  a  German  machine.  The  German  pilot  was 
killed  and  the  plane  fell  behind  the  French 
lines,  carrying  with  it  a  Prussian  nobleman 
who  died  before  he  could  be  pulled  out  of  the 
wreckage.  The  war  had  been  carried  into  the 
skies.  But  if  scouts  were  to  fight  one  another, 
they  could  not  pay  much  attention  to  scouting 
and  spotting  and  it  began  to  be  realized  that 
there  were  four  distinct  classes  of  work  for  the 
airplane  to  do — scouting,  artillery-spotting,  bat- 
tling, and  bombing.  Each  called  for  special 
training  and  its  own  type  of  machine.  As  air 
fighting  grew  more  specialized  these  classes 
were  further  subdivided,  but  we  need  not  go  into 
such  refinements. 


128      INVENTIONS  OF  THE  GREAT  WAR 

AIR   SCOUTS   AND   THEIE   DANGERS 

The  scouting-airplane  usually  carried  two 
men,  one-  to  drive  -the  machine  and  the  other  to 
make  observations.  The  observer  had  to  carry 
a  camera,  to  take  photographs  of  what  lay  be- 
low, and  he  was  usually  equipped  with  a  wire- 
less outfit,  with  which  he  could  send  important 
information  back  to  his  own  base.  The  camera 
was  sometimes  fitted  with  a  stock  like  that  of 
a  gun,  so  that  it  could  be  aimed  from  the 
shoulder.  Some  small  cameras  were  shaped  so 
that  they  could  be  held  in  the  hand  like  a  pistol 
and  aimed  over  the  side  of  the  fuselage,  or  body, 
of  the  airplane ;  but  the  best  work  was  done  with 
large  cameras  fitted  with  telescopic  lenses,  or 
"telephoto"  lenses,  as  they  are  called.  Some 
of  these  were  built  into  the  airplane,  with  the 
lens  opening  down  through  the  bottom  of  the 
fuselage. 

The  scouting-airplane  carried  a  machine-gun, 
not  for  attack,  but  for  defense.  It  had  to  be  a 
quick  climber  and  a  good  dodger,  so  that  it 
could  escape  from  an  attacking  plane.  Usually 
it  did  not  have  to  go  very  far  into  the  enemy 
country,  and  it  was  provided  with  a  large  wing- 


How  an  object  dropped  from  the  Woolworth  Building  would 
increase  its  speed  in  falling 


THE  WAfc  IN  THE  AIR 

spread,  so  that  if  anything  happened  to  the 
engine,  it  could  volplane,  or  glide  back,  to  its 
own  lines.  As  the  scouting-planes  were  large, 
they  offered  a  big  target  to  anti-aircraft  guns, 
and  so  the  work  of  the  air  scout  was  to  swoop 
down  upon  the  enemy,  when,  of  course,  the 
machine  would  be  traveling  at  high  velocity, 
because  it  would  have  all  the  speed  of  falling 
added  to  that  which  its  own  propeller  gave  it. 

It  was  really  a  very  difficult  matter  to  hit  a 
rapidly  moving  airplane;  and  even  if  it  were 
hit,  there  were  few  spots  in  which  it  could  be 
mortally  wounded.  Hundreds  of  shots  could  go 
through  the  wings  of  an  airplane  without  im- 
pairing its  flying  in  the  least.  The  engine,  too, 
could  be  pretty  well  peppered  with  ordinary 
bullets  without  being  disabled.  As  for  -the  men 
in  the  machine,  they  furnished  small  targets, 
and  even  they  could  be  hit  in  many  places  with- 
out being  put  entirely  out  of  business.  And  so 
the  dangers  of  air  scouting  were  not  so  great 
as  might  at  first  be  supposed. 

One  of  the  most  vulnerable  spots  in  the  air- 
plane was  the  gasolene  tank.  If  that  were 
punctured  so  that  the  fuel  would  run  out,  the 
airplane  would  have  to  come  to  the  ground. 


130      INVENTIONS  OF  THE  GREAT  WAR 

Worse  still,  the  gasolene  might  take  fire  and 
there  was  nothing  the  aviator  dreaded  more 
than  fire.  There  were  occasions  in  which  he  had 
to  choose  between  leaping  to  earth  and  burn- 
ing to  death,  and  the  former  was  usually  pre- 
ferred as  a  quicker  and  less  painful  death. 
In  some  of  the  later  machines  the  gasolene-tank 
could  be  pitched  overboard  if  it  took  fire,  by  the 
throwing  of  a  lever,  and  then  the  aviator  could 
glide  to  earth  in  safety. 

THE   SELF-HEALING   GASOLENE-TANK 

One  of  the  contributions  which  we  made  to 
military  aeronautics  was  a  gasolene-tank  that 
was  puncture-proof.  It  was  made  of  soft  rub- 
ber with  a  thin  lining  of  copper.  There  are 
some  very  soft  erasers  on  the  market  through 
which  you  can  pass  a  lead  pencil  and  never  find 
the  hole  after  it  has  passed  through,  because 
the  rubber  has  closed  in  and  healed  the  wound. 
Such  was  the  rubber  used  in  the  gasolene-tank. 
It  could  be  peppered  with  bullets  and  yet  would 
not  leak  a  drop  of  gasolene,  unless  the  bullet 
chanced  to  plow  along  the  edge  of  the  tank 
and  open  a  long  gash. 

The  Germans  used  four  different  kinds  of 


THE  WAR  IN  THE  AIR  131 

cartridges  in  their  aircraft  guns.  The  first 
carried  the  ordinary  bullet,  a  second  type  had 
for  its  bullet  a  shell  of  German  silver  filled  with 
a  phosphor  compound.  This  was  automatically 
ignited  through  a  small  opening  in  the  base  of 
the  shell  when  it  was  fired  from  the  gun  and  it 
left  a  trail  of  smoke  by  which  the  gunner  could 
trace  its  course  through  the  air  and  correct  his 
aim.  At  night  the  bright  spot  of  light  made 
by  the  burning  compound  would  serve  the  same 
purpose.  Such  a  bullet,  if  it  hit  an  ordinary 
gasolene-tank,  would  set  fire  to  its  contents. 
The  bullet  would  plow  through  the  tank  and  out 
at  the  opposite  side  and  there,  at  its  point  of 
exit,  is  where  the  gasolene  would  be  set  on 
fire.  Such  incendiary  bullets  were  repeatedly 
fired  into  or  through  the  rubber  tanks  and  the 
hole  would  close  behind  the  bullet,  preventing 
the  contents  from  taking  fire.  The  two  other 
types  of  bullets  referred  to  were  an  explosive 
bullet  or  tiny  shell  which  would  explode  on 
striking  -the  target  and  a  perforating  steel  bul- 
let which  was  intended  to  pierce  armor  or  pene- 
trate into  vital  parts  of  an  airplane  engine. 

Machines  with  which  artillery-spotting  was 
done  were  usually  manned  by  a  pilot  and  an  ob- 


132      INVENTIONS  OF  THE  GREAT  WAR 

server,  so  that  the  latter  could  devote  his  entire 
attention  to  noting  the  fire  of  the  guns  and 
signaling  ranges  without  being  hampered  by 
having  to  drive  the  machine.  These  machines 
were  usually  of  the  pusher  type,  so  that  the  ob- 
server could  have  an  unobstructed  view.  They 
did  not  have  to  be  fast  machines.  It  was  really 
better  for  them  to  move  slowly.  Had  it  been 
possible  for  them  to  stop  altogether  and  hover 
over  the  spot  that  was  being  shelled,  it  would 
have  been  a  distinct  advantage.  That  would 
have  given  the  observer  a  chance  to  note  with 
better  accuracy  the  fall  of  the  shell.  Like  the 
scout,  -the  spotter  had  to  be  a  fast  climber,  so 
that  it  could  get  out  of  the  range  of  enemy  guns 
and  run  away  from  attacking  planes. 

GIANTS   OF   THE   SKY 

The  largest  war-planes  were  the  bomb-drop- 
ping machines.  They  had  to  be  capable  of 
carrying  heavy  loads  of  explosives.  They  were 
usually  slow  machines,  speed  being  sacrificed 
in  carrying-capacity. 

The  Germans  paid  a  great  deal  of  attention 
to  big  bomb-dropping  machines,  particularly 
after  their  Zeppelins  proved  a  failure.  Their 


THE  WAR  IN  THE  AIR  133 

huge  Gothas  were  built  to  make  night  raids  on 
undefended  cities.  The  Italians  and  the  British 
retaliated  with  machines  that  were  even  larger. 
At  first  the  French  were  inclined  to  let  giant 
planes  alone.  They  did  not  care  to  conduct 
long-distance  bombing-raids  on  German  cities 
because  their  own  important  cities  were  so  near 
the  battle-front  that  the  Germans  could  have 
done  those  places  more  harm  than  the  French 
could  have  inflicted.  Later  they  built  some 
giant  machines,  although  not  so  large  as  those 
of  the  Italians  and  the  British. 

The  large  triplane  Capronis  built  by  the 
Italians  held  a  crew  of  three  men.  They  were 
armed  with  three  guns  and  carried  2750  pounds 
of  explosives.  That  made  a  useful  load  of  4000 
pounds.  The  machine  was  driven  by  three  en- 
gines with  a  total  of  900  horse-power. 

The  big  British  plane  was  the  Handley-P-age, 
which  had  a  wing-spread  of  125  feet  and  could 
carry  a  useful  load  of  three  tons.  These  enor- 
mous machines  conducted  their  raids  at  night 
because  they  were  comparatively  slow  and  could 
not  defend  themselves  against  speedy  battle- 
planes. The  big  Italian  machines  used  * i  search- 
light "  bombs  to  help  them  locate  important 


134     INVENTIONS  OF  THE  GREAT  WAR 

points  on  the  ground  beneath.  These  were 
brilliant  magnesium  torches  suspended  from 
parachutes  so  that  they  would  fall  slowly  and 
give  a  broad  illumination,  while  the  airplane  it- 
self was  shielded  from  the  light  by  the  para- 
chute. 

But  these  giants  were  not  the  only  bombing- 
machines.  There  were  smaller  machines  that 
operated  over  the  enemy's  battle-line  and 
dropped  bombs  on  any  suspicious  object  behind 
the  enemy  lines.  These  machines  had  to  be  con- 
voyed by  fast  battle-planes  which  fought  off 
hostile  airmen. 

HOW    FAST   IS   A   HUNDRED   AND   FIFTY   MILES 
PER   HOUR? 

In  naval  warfare  the  battle-ship  is  the  big- 
gest and  heaviest  ship  of  the  fleet,  but  in  the 
air  the  battle-planes  are  the  lightest  and  the 
smallest  of  the  lot.  They  are  one-man  ma- 
chines, as  a  rule,  little  fellows,  but  enormously 
speedy.  Speed  is  such  an  important  factor  in 
aerial  warfare  that  there  was  a  continuous 
struggle  between  the  opposing  forces  to  pro- 
duce the  faster  machine.  Airplanes  were  con- 
stantly growing  speedier,  until  a  speed  of  150 


THE  WAR  IN  THE  AIR  135 

miles  per  hour  was  not  an  uncommon  rate  of 
travel.  It  is  hard  to  imagine  such  a  speed  as 
that,  but  we  may  gain  some  idea  if  we  consider 
a  falling  object.  The  observation  platform  of 
the  Woolworth  Building,  in  New  York,  is  about 
750  feet  above  'the  ground.  If  you  should  drop 
an  object  from  this  platform  you  would  start 
it  on  a  journey  that  would  grow  increasingly 
speedy,  particularly  as  it  neared  the  ground. 
By  the  time  it  had  dropped  from  the  sixtieth 
story  to  the  fifty-ninth  it  would  have  attained  a 
speed  of  nearly  20  miles  per  hour.  (We  are  not 
making  any  allowances  for  the  resistance  of  the 
air  and  what  it  would  do  to  check  the  speed.)  As 
it  passed  the  fiftieth  story  it  would  be  traveling 
as  fast  as  an  express-train,  or  60  miles  per  hour. 
It  would  finally  reach  the  ground  with  a  speed 
equal  to  that  of  a  fast  battle-plane — 150  miles 
per  hour. 

The  battle-plane  was  usually  fitted  with  a 
single  machine-gun  that  was  fixed  to  the  air- 
plane, so  that  it  was  brought  to  bear  on  the 
target  by  aiming  the  entire  machine.  In  this  the 
plane  was  something  like  a  submarine,  which 
must  point  its  bow  at  its  intended  victim  in  or- 
der to  aim  its  torpedo.  The  operator  of  the  bat- 


136      INVENTIONS  OF  THE  GREAT  WAR 

tie-plane  simply  drove  his  machine  at  the  enemy 
and  touched  a  button  on  his  steering-lever  to 
start  his  machine-gun  going. 

SHOOTING   THROUGH   THE   PROPELLER 

Now,  the  fleetest  machines  and  the  most  easily 
maneuvered  are  those  of  the  tractor  type,  that 
is,  the  ones  which  have  the  propeller  in  front; 
but  having  the  propeller  in  front  is  a  handicap 
for  a  single-seater  machine,  for  the  gun  has  to 
be  fired  through  the  propeller  and  the  bullets 
are  sure  to  hit  the  propeller-blades.  Neverthe- 
less the  French  did  fire  right  through  the  pro- 
peller, regardless  of  whether  or  not  the  blades 
were  hit;  but  at  the  point  where  they  came  in 
line  with  the  fire  of  the  gun  they  were  armored 
with  steel,  so  that  there  was  no  danger  of  their 
being  cut  by  the  bullets.  It  was  calculated  that 
not  more  than  one  bullet  in  eighteen  would  strike 
the  propeller-blade  and  be  deflected  from  its 
course,  which  was  a  very  trifling  loss ;  neverthe- 
less, it  was  a  loss,  and  on  this  account  a  mechan- 
ism was  devised  which  would  time  the  opera- 
tions of  the  machine-gun  so  that  the  shots  would 
come  only  when  the  propeller-blades  were  clear 
of  the  line  of  fire. 


Machine  Gun  mounted  to  Fire  over  the   Blades  of  the  Propeller 


Courtesy  of  "Scientific  American  " 

Mechanism  for  Firing  Between  the  Blades  of  the  Propeller 

The  cam  B  on  the  propeller  shaft  lifts  the  rod  C,  rocking  the  angle 
lever  D  which  moves  the  rod  E  and  operates  the  firing-piece  F. 
Firing  may  be  stopped  by  means  of  lever  Hand  Bowden  wire  G. 
I  is  the  ejection-tube  for  empty  cartridges. 


I 

•Si 


THE  WAR  IN  THE  AIR  137 

A  cam  placed  on  the  propeller-shaft  worked 
the  trigger  of  the  machine-gun.  This  did  not 
slow  up  the  fire  of  the  machine-gun.  Quite  the 
contrary.  We  are  apt  to  think  of  the  fire  of  the 
machine-guns  as  very  rapid,  but  they  usually 
fire  only  about  five  hundred  rounds  per  minute, 
while  an  airplane  propeller  will  make  something 
like  twelve  hundred  revolutions  per  minute. 
And  so  the  mechanism  was  arranged  to  pull  the 
trigger  only  once  for  every  two  revolutions  of 
the  propeller. 

FIGHTING   AMONG   THE    CLOUDS 

There  was  no  service  of  the  war  that  began  to 
compare  with  that  of  the  sky  fighter.  He  had 
to  climb  to  enormous  heights.  Air  battles  took 
place  at  elevations  of  twenty  thousand  feet. 
The  higher  the  battle-plane  could  climb,  the  bet- 
ter, because  the  man  above  had  a  tremendous 
advantage.  Clouds  were  both  a  haven  and  a 
menace  to  him.  At  any  moment  an  enemy  plane 
might  burst  out  of  the  cloufds  upon  him.  He 
had  to  be  ready  to  go  through  all  the  thrilling 
tricks  of  a  circus  performer  so  as  to  dodge  the 
other  fellow  and  get  a  commanding  position. 
Jf  he  were  getting  ttye  worst  of  it,  he  might 


138      INVENTIONS  OF  THE  GREAT  WAR 

feign  death  and  let  his  machine  go  tumbling  and 
fluttering  down  for  a  thousand  feet  or  so,  only 
to  recover  his  equilibrium  suddenly  and  dart 
away  when  the  enemy  was  thrown  off  his  guard. 
He  might  escape  into  some  friendly  cloud,  but 
he  dared  not  hide  in  it  very  long,  lest  he  get 
lost. 

It  is  a  peculiar  sensation  that  comes  over  an 
aviator  when  he  is  flying  through  a  thick  mass 
of  clouds.  He  is  cut  off  from  the  rest  of  the 
world.  He  can  hear  nothing  but  the  terrific 
roar  of  his  own  motor  and  the  hurricane  rush 
of  the  wind  against  his  ears.  He  can  see 
nothing  but  the  bluish  fog  of  the  clouds.  He 
begins  to  lose  all  sense  of  direction.  His  com- 
pass appears  to  swing  violently  to  and  fro,  when 
really  it  is  his  machine  that  is  zig-zagging  under 
his  unsteady  guidance.  The  more  he  tries  to 
steady  it,  the  worse  becomes  the  swing  of  the 
compass.  As  he  turns  he  banks  his  machine 
automatically,  just  as  a  bicyclist  does  when 
rounding  a  corner.  He  does  this  unconsciously, 
and  he  may  get  to  spinning  round  and  round, 
with  his  machine  standing  on  its  side.  In  some 
cases  aviators  actually  emerged  from  the  clouds 
with  their  machines  upside  down.  To  be  sure, 


THE  WAR  IN  THE  AIR  139 

this  was  not  an  alarming  position  for  an  expe- 
rienced aviator ;  at  the  same  time,  it  was  not  al- 
together a  safe  one.  A  machine  was  some- 
times broken  by  its  operator's  effort  to  right  it 
suddenly.  And  so  while  the  clouds  made  handy 
shelters,  they  were  not  always  safe  harbors. 

To  the  battle-plane  fell  the  task  of  clearing 
the  air  of  the  enemy.  If  the  enemy's  battle- 
planes were  disposed  of,  his  bombing-planes, 
his  spotters,  and  his  scouts  could  not  operate, 
and  he  would  be  blind.  And  so  each  side  tried 
to  beat  out  the  other  with  speedier,  more  power- 
ful, and  more  numerous  battle-planes.  Fast 
double-seaters  were  built  with  guns  mounted  so 
that  they  could  turn  in  any  direction. 

THE   FLYING   TANK 

The  Germans  actually  built  an  armored  bat- 
tle-plane known  as  the  flying  tank.  It  was  a 
two-seater  intended  mainly  for  attacking  in- 
fantry and  was  provided  with  two  machine- 
guns  that  pointed  down  through  the  floor  of  the 
fuselage.  A  third  gun  mounted  on  a  revolving 
wooden  ring  could  be  used  to  fight  off  hostile 
planes.  The  bottom  and  sides  of  the  fuselage 
or  body  of  the  airplane  from  the  gunner's  cock- 


140     INVENTIONS  OF  THE  GREAT  WAK 

pit  forward  were  sheathed  with  plates  of  steel 
armor.  The  machine  was  a  rather  cumbersome 
craft  and  did  not  prove  very  successful.  A  fly- 
ing tank  was  brought  down  within  the  American 
lines  just  before  the  signing  of  the  armistice. 

AMERICA'S  HELP 

Our  own  contribution  to  the  war  in  the  air 
was  considerable,  but  we  had  hardly  started  be- 
fore the  armistice  brought  the  fighting  to  an 
end.  Before  we  entered  the  war  we  did  not 
give  the  airplane  any  very  serious  considera- 
tion. To  be  sure,  we  built  a  large  number  of 
airplanes  for  the  British,  but  they  were  not 
good  enough  to  be  sent  to  the  front ;  they  were 
used  merely  as  practice  planes  in  the  British 
training-schools.  We  knew  that  we  were  hope- 
lessly outclassed,  but  we  did  not  care  very 
much.  Then  we  stepped  into  the  conflict. 

"What,  can  we  do  to  help?"  we  asked  our 
allies,  and  their  answer  gave  us  a  shock. 

" Airplanes !"  they  cried.  "  Build  us  air- 
planes— thousands  of  them — so  that  we  can 
drive  the  enemy  out  of  the  air  and  blind  his 
armies!" 

It  took  us  a  while  to  recover  from  our  sur- 


THE  WAR  IN  THE  AIR  141 

prise,  and  then  we  realized  why  we  had  been 
asked  to  build  airplanes.  The  reputation  of  the 
United  States  as  a  manufacturer  of  machinery 
had  spread  throughout  the  world.  We  Ameri- 
cans love  to  take  hold  of  a  machine  and  turn  it 
out  in  big  quantities.  Our  allies  were  sure  that 
we  could  turn  out  first-class  airplanes,  and  many 
of  them,  if  we  tried. 

Congress  made  an  appropriation  of  six  hun- 
dred and  forty  million  dollars  for  aeronautics, 
and  then  things  began  to  hum. 

A  BIRTHDAY   PRESENT    TO    THE   NATION 

The  heart  of  an  airplane  is  its  engine.  We 
know  a  great  deal  about  gasolene-engines,  es- 
pecially automobile  engines ;  but  an  airplane  en- 
gine is  a  very  different  thing.  It  must  be  tre- 
mendously powerful,  and  at  the  same  time  ex- 
tremely light.  Every  ounce  of  unnecessary 
weight  must  be  shaved  off.  It  must  be  built 
with  the  precision  of  a  watch;  its  vital  parts 
must  be  true  xo  a  ten-thousandth  part  of  an  inch. 
It  takes  a  very  powerful  horse  to  develop  one 
horse-power  for  a  considerable  length  of  time. 
It  would  take  a  hundred  horses  to  supply  the 
power  for  even  a  small  airplane,  and  they  would 


142      INVENTIONS  OF  THE  GREAT  WAR 

weigh  a  hundred  and  twenty  thousand  pounds. 
An  airplane  motor  of  the  same  power  would 
weigh  less  than  three  hundred  pounds,  which  is 
a  quarter  of  the  weight  of  a  single  horse.  It 
was  this  powerful,  yet  most  delicate,  machine 
that  we  were  called  upon  to  turn  out  by  the  thou- 
sand. There  was  no  time  to  waste;  a  motor 
must  be  designed  that  could  be  built  in  the 
American  way,  without  any  tinkering  or  fussy 
hand-work. 

Two  of  our  best  engineers  met  in  a  hotel  in 
Washington  on  June  3,  1917,  and  worked  for 
five  days  without  once  leaving  their  rooms. 
They  had  before  them  all  the  airplane  knowl- 
edge of  our  allies.  American  engine-builders 
offered  up  their  trade  secrets.  Everything  was 
done  to  make  this  motor  worthy  of  America's 
reputation.  There  was  a  race  to  have  the  mo- 
tor finished  by  the  Fourth  of  July.  Sure 
enough,  on  Independence  Day  the  finished  motor 
was  there  in  Washington — the  "Liberty  mo- 
tor, "  a  birthday  present  to  the  nation. 

Of  course  that  did  not  mean  that  we  were 
ready  at  once  to  turn  out  Liberty  motors  by  the 
thousand.  The  engine  had  to  undergo  many 
tests  and  a  large  number  of  alterations  before  it 


THE  WAR  IN  THE  AIR  143 

was  perfectly  satisfactory  and  then  special  ma- 
chinery had  to  be  constructed  before  it  could 
be  manufactured  in  quantity.  It  was  Thanks- 
giving Day  before  the  first  manufactured  Lib- 
erty was  turned  out  and  even  after  that  change 
upon  change  was  made  in  this  little  detail  and 
that.  It  was  not  until  a  year  after  we  went  to 
war  that  the  engine  began  to  be  turned  out  in 
quantity. 

There  was  nothing  startlingly  new  about  the 
engine.  It  was  a  composite  of  a  number  of 
other  engines,  but  it  was  designed  to  be  turned 
out  in  enormous  quantities,  and  it  was  remark- 
ably efficient.  It  weighed  only  825  pounds  and 
it  developed  over  420  horse-power.  Some  ma- 
chines went  up  as  high  as  485  horse-power.  An 
airplane  engine  weighing  less  than  2  pounds  per 
horse-power  is  wonderfully  efficient.  Of  course 
the  Liberty  was  too  heavy  for  a  light  battle- 
plane (a  heavy  machine,  no  matter  how  power- 
ful, cannot  make  sharp  turns),  but  it  was  ex- 
cellent for  other  types  of  airplanes  and  large 
orders  for  Liberty  engines  were  made  by  our 
allies.  Of  course  we  made  other  engines  as 
well,  and  the  planes  to  carry  them.  We  built 
large  Caproni  and  Handley-Page  machines,  and 


144     INVENTIONS  OF  THE  GEEAT  WAR 

we  were  developing  some  remarkably  swift  and 
powerful  planes  of  our  own  when  the  Germans 
thought  it  about  time  to  stop  fighting. 

FLYING  BOATS 

So  far  we  have  said  nothing  about  the  sea- 
planes which  were  used  in  large  numbers  to 
watch  for  submarines.  These  were  big  flying 
boats  in  which  speed  was  not  a  very  important 
matter.  One  of  the  really  big  machines  we  de- 
veloped, but  which  was  not  finished  until  after 
the  war,  was  a  giant  with  a  110-foot  span  and 
a  body  or  hull  50  feet  long.  During  the  war 
seaplanes  carried  wireless  telephone  apparatus 
with  which  they  could  call  to  destroyers  and  sub- 
marine-chasers when  they  spotted  a  submarine. 
They  also  carried  bombs  which  they  could  drop 
on  U-boats,  and  even  heavy  guns  with  which 
they  could  fire  shell. 

A  still  later  development  are  the  giant  planes 
of.  the  N.  C.  type  with  a  wing-spread  of  126 
feet  and  driven  by  four  Liberty  motors.  They 
carry  a  useful  load  of  four  and  a  half  tons. 

Early  in  the  war,  large  guns  were  mounted 
on  airplanes,  but  the  shock  of  the  recoil  proved 
too  much  for  the  airplane  to  stand.  However, 


C)  Uriderwood  &  Underwood 

The   Flying-tank  —  an    Armored    German    Airplane    designed 
for  firing  on  troops  on  the  march 


THE  WAR  IN  THE  AIR  145 

an  American  inventor  produced  a  gun  which 
had  no  recoil.  This  he  accomplished  by  using 
a  double-end  gun,  which  was  fired  from  the  mid- 
dle. The  bullet  or  shell  was  shot  out  at  the 
forward  end  of  the  gun  and  a  dummy  charge 
of  sand  was  shot  out  at  the  rear  end.  The  sand 
spread  out  and  did  no  damage  at  a  short  dis- 
tance from  the  gun,  but  care  had  to  be  taken 
not  to  come  too  close.  These  non-recoil  guns 
were  made  in  different  sizes,  to  fire  1%-inch  to 
3-inch  shell. 

THE   AUTOMATIC    SEAPLANE 

Another  interesting  development  was  the  tar- 
get airplane  used  for  the  training  of  aerial  gun- 
ners. This  was  a  small  seaplane  with  a  span 
of  only  18y2  feet,  driven  by  a  12-horse-power 
motor,  the  whole  machine  weighing  but  175 
pounds.  This  was  sent  up  without  a  pilot  and 
it  would  fly  at  the  rate  of  forty  to  fifty  miles 
per  hour  until  its  supply  of  gasolene  gave  out, 
when  it  would  drop  down  into  the  sea.  It  af- 
forded a  real  target  for  gunners  in  practice 
machines. 

Early  in  the  war  an  American  inventor  pro- 
posed that  seaplanes  be  provided  with  torpedoes 


146      INVENTIONS  OF  THE  GREAT  WAR 

which  they  could  launch  at  an  enemy  ship.  The 
seaplane  would  swoop  down  out  of  the  sky  to 
within  a  short  distance  of  the  ship,  drop  its  pro- 
jecticle,  and  fly  off  again,  and  the  torpedo  would 
continue  on  its  course  until  it  blew  up  the  vessel. 
It  was  urged  that  a  fleet  of  such  seaplanes  pro- 
tected by  a  convoy  of  fast  battle-planes  could 
invade  the  enemy  harbors  and  destroys  its  pow- 
erful fleet.  It  seemed  like  a  rather  wild  idea, 
but  the  British  actually  built  such  torpedo- 
planes  and  tested  them.  However,  the  German 
fleet  surrendered  before  it  was  necessary  to 
blow  it  up  in  such  fashion. 

AIRPLANES   AFTER   THE    WAR 

With  the  war  ended,  all  the  Allied  powers 
have  large  numbers  of  airplanes  on  their  hands 
and  also  large  numbers  of  trained  aviators. 
Undoubtedly  airplanes  will  continue  to  fill  the 
skies  in  Europe  and  we  shall  see  more  and  more 
of  them  in  this  country.  Even  during  the  war 
they  were  used  for  other  purposes  than  fighting. 
There  were  ambulances  on  wings — machines 
with  the  top  of  the  fuselage  removable  so  that 
a  patient  on  a  stretcher  could  be  placed  inside. 
A  French  machine  was  furnished  with  a  com- 


THE  WAR  IN  THE  AIR  147 

plete  hospital  equipment  for  emergency  treat- 
ment and  even  for  performing  an  operation  in 
case  of  necessity.  The  flying  hospital  could 
carry  the  patient  back  to  the  field  or  base  hos- 
pital after  treatment. 

Mail-carrying  airplanes  are  already  an  old 
story.  In  Europe  the  big  bombing-machines 
are  being  used  for  passenger  service  between 
cities.  There  is  an  air  line  between  Paris  and 
London.  The  airplanes  carry  from  a  dozen  to 
as  many  as  fifty  passengers  on  a  single  trip.  In 
some  cities  here,  as  well  as  abroad,  the  police 
are  being  trained  to  fly,  so  that  they  can  police 
the  heavens  when  the  public  takes  to  wings. 
Evidently  the  flying-era  is  here. 


CHAPTER  VIII 

SHIPS  THAT  SAIL  THE  SKIES 

SHORTLY  after  the  Civil  War  broke  out, 
Thaddeus  S.  C.  Lowe,  an  enthusiastic 
American  aeronaut,  conceived  the  idea  of  send- 
ing up  scout  balloons  to  reconnoiter  the  posi- 
tion of  the  enemy.  These  balloons  were  to  be 
connected  by  telegraph  wires  with  the  ground, 
so  that  they  could  direct  the  artillery  fire.  The 
idea  was  so  novel  to  the  military  authorities  of 
that  day  that  it  was  not  received  with  favor. 
Balloons  were  looked  upon  as  freak  inventions, 
entirely  impracticable  for  the  stern  realities 
of  war ;  and  as  for  telegraphing  from  a  balloon, 
no  one  had  ever  done  that  before. 

But  this  enthusiast  was  not  to  be  daunted, 
and  he  made  a  direct  appeal  to  President  Lin- 
coln, offering  to  prove  the  practicability  of  this 
means  of  scouting.  So  he  took  his  balloon  to 
Washington  and  made  an  ascent  from  the 
grounds  of  the  Smithsonian  Institution,  while 

148 


eourtesy  ot  "Scientific  American  " 

Observation  Car  lowered  from  a  Zeppelin  sailing 
above  the  clouds 


SHIPS  THAT  SAIL  THE  SKIES         149 

the  President  came  out  on  the  lawn  south  of  the 
White  House  to  watch  the  demonstration.  In 
order  to  test  him,  Mr.  Lincoln  took  off  his  hat, 
waved  his  handkerchief,  and  made  other  signals. 
Lowe  observed  each  act  through  his  field-glasses 
and  reported  it  to  the  President  by  telegraph. 
Mr.  Lincoln  was  so  impressed  by  the  demonstra- 
tion that  he  ordered  the  army  to  use  the  ob- 
servation balloon,  and  so  with  some  reluctance 
the  gas-bag  was  introduced  into  military  serv- 
ice, Professor  Lowe  being  made  chief  aeronautic 
engineer.  Under  Lowe's  direction  the  observa- 
tion balloons  played  an  important  part  in  the 
operations  of  the  Union  Army. 

On  one  occasion  a  young  German  military 
attache  begged  the  privilege  of  making  an  as- 
cent in  the  balloon.  Permission  was  given  and 
when  the  German  officer  returned  to  earth  he 
was  wildly  enthusiastic  in  praise  of  this  aerial 
observation  post.  He  had  had  a  splendid  view 
of  the  enemy  and  could  watch  operations 
through  his  field-glasses  which  were  of  utmost 
importance.  Realizing  the  military  value  of 
the  aircraft,  he  returned  to  Germany  and  urged 
military  authorities  to  provide  themselves  with 
captive  balloons.  This  young  officer  was  Count 


150      INVENTIONS  OF  THE  GREAT  WAR 

Ferdinand  von  Zeppelin,  who  was  destined  later 
to  become  the  most  famous  aeronautic  authority 
in  the  world  and  who  lived  to  see  Germany 
equipped  with  a  fleet  of  balloons  which  were 
self-propelling  and  could  travel  over  land  and 
sea  to  spread  German  frightfulness  into  Eng- 
land. He  also  lived  to  see  the  virtual  failure 
of  this  type  of  war-machine  in  the  recent  great 
conflict,  and  it  was  possibly  because  of  his  deep 
disappointment  at  having  his  huge  expensive 
airships  bested  by  cheap  little  airplanes  that 
Count  von  Zeppelin  died  in  March,  1917.  How- 
ever, he  was  spared  the  humiliation  of  seeing  a 
fleet  of  Zeppelins  lose  their  way  in  a  fog  and 
fall  into  France,  one  of  them  being  captured  be- 
fore it  could  be  destroyed,  so  that  all  its  secrets 
of  construction  were  learned  by  the  French. 

THE    WEIGHT    OF    HYDROGEN 

Before  we  describe  the  Zeppelin  airships  and 
the  means  by  which  they  were  eventually  over- 
come, we  must  know  something  about  the  prin- 
ciples of  balloons.  Every  one  knows  that  bal- 
loons are  kept  up  in  the  air  by  means  of  a  very 
light  gas,  but  somehow  the  general  public  fails 
to  understand  why  the  gas  should  hold  it  up. 


SHIPS  THAT  SAIL  THE  SKIES         151 

Some  people  have  a  notion  that  there  is  some- 
thing, mysterious  about  hydrogen  gas  which 
makes  it  resist  the  pull  of  gravity,  and  that  the 
more  hydrogen  you  crowd  into  the  balloon  the 
more  weight  it  will  lift.  But  hydrogen  has 
weight  and  feels  the  pull  of  gravity  just  as  air 
does,  or  water,  or  lead.  The  only  reason  the 
balloon  rises  is  because  it  weighs  less  than  the 
air  it  displaces.  It  is  hard  to  think  of  air 
as  having  weight,  but  if  we  weigh  air,  hydrogen, 
coal-gas,  or  any  other  gas,  in  a  vacuum,  it  will 
tip  the  scales  just  as  a  solid  would.  A  thousand 
cubic  feet  of  air  weighs  80  pounds.  In  other 
words,  the  air  in  a  room  ten  feet  square  with  a 
ceiling  ten  feet  high,  weighs  just  about  80 
pounds.  The  same  amount  of  coal-gas  weighed 
in  a  vacuum  would  register  only  40  pounds; 
while  an  equal  volume  of  hydrogen  would  weigh 
only  51/2  pounds.  But  when  we  speak  of  vol- 
umes of  gas  we  must  remember  that  gas,  unlike 
a  liquid  or  a  solid,  can  be  compressed  or  ex- 
panded to  almost  any  dimensions.  For  in- 
stance, we  could  easily  fill  our  room  with  a  ton 
of  air  if  the  walls  would  stand  the  pressure ;  or 
we  could  pump  out  the  air,  until  there  were  but 
a  few  ounces  of  air  left.  But  in  one  case  the 


152      INVENTIONS  OF  THE  GREAT  WAR 

air  would  be  so  highly  compressed  that  it  would 
exert  a  pressure  of  about  375  pounds  on  every 
square  inch  of  the  wall  of  the  room,  while  in 
the  other  case  its  pressure  would  be  almost  in- 
finitesimal. But  80  pounds  of  air  in  a  room 
of  a  thousand  cubic  feet  would  exert  the  same 
pressure  as  the  atmosphere,  or  15  pounds  on 
every  square  inch.  And  when  we  say  that  a 
thousand  cubic  feet  of  hydrogen  weighs  only  a 
little  over  5  pounds,  we  are  talking  about  hydro- 
gen at  the  same  pressure  as  the  atmosphere. 

Since  the  hydrogen  is  sixteen  times  lighter 
than  air,  naturally  it  will  float  in  the  air,  just  as 
a  piece  of  wood  will  float  in  water  because  it  is 
lighter  than  the  same  volume  of  water.  If  we 
surrounded  the  thousand  cubic  feet  of  hydro- 
gen with  a  bag  so  that  the  gas  will  not  diffuse 
into  the  air  and  mix  with  it,  we  shall  have  a 
balloon  which  would  float  in  air  provided  the  bag 
and  the  hydrogen  it  contains  do  not  weigh  more 
than  eighty  pounds.  As  we  rise  from  the  sur- 
face of  the  earth,  the  air  becomes  less  and  less 
dense,  or,  in  other  words,  it  becomes  lighter, 
and  the  balloon  will  keep  on  rising  through  the 
atmosphere  until  it  reaches  a  point  at  which  its 


SHIPS  THAT  SAIL  THE  SKIES          153 

weight,  gas-bag  and  all,  is  exactly  the  same  as 
that  of  an  equal  volume  of  air. 

But  there  are  many  conditions  that  affect  the 
height  to  which  the  balloon  will  ascend.  The 
higher  we  rise,  the  colder  it  is  apt  to  become, 
and  cold  has  a  tendency  to  compress  the  hydro- 
gen, collapsing  the  balloon  and  making  it  rela- 
tively heavier.  When  the  sun  beats  upon  a  bal- 
loon, it  heats  the  hydrogen,  expanding  it  and 
making  it  relatively  lighter,  and  if  there  is 
no  room  for  this  expansion  to  take  place  in  the 
bag,  the  bag  will  burst.  For  this  reason,  a  big 
safety-valve  must  be  provided  and  the  ordinary 
round  balloon  is  open  at  the  bottom  so  that  the 
hydrogen  can  escape  when  it  expands  too  much 
and  the  balloonist  carries  ballast  in  the  form  of 
sand  which  he  can  throw  over  to  lighten  the 
balloon  when  the  gas  is  contracted  by  a  sudden 
draft  of  cold  air. 

Although  a  round  balloon  carries  no  engine 
and  no  propeller,  it  can  be  guided  through  the 
air  to  some  degree.  When  an  aeronaut  wishes 
to  go  in  any  particular  direction,  he  sends  up 
his  balloon  by  throwing  out  ballast  or  lowers  it 
by  letting  out  a  certain  amount  of  gas,  until 


154      INVENTIONS  OF  THE  GKEAT  WAR 

he  reaches  a  level  at  which  he  finds  a  breeze 
blowing  in  the  desired  direction.  Such  was 
the  airship  of  Civil  War  times,  but  for  mili- 
tary purposes  it  was  not  advisable  to  use  free 
balloons,  because  of  the  difficulty  of  controlling 
them.  They  were  too  liable  to  fall  into  the 
hands  of  the  enemy.  All  that  was  needed  was 
a  high  observation  post  from  which  the  enemy 
could  be  watched,  and  from  which  observations 
could  be  reported  by  telegraph.  The  balloon 
was  not  looked  upon  as  a  fighting-machine. 

ZEPPELIN'S  FAILURES  AND  SUCCESSES 

But  Count  Zeppelin  was  a  man  of  vision.  He 
dreamed  of  a  real  ship  of  the  air — a  machine 
that  would  sail  wherever  the  helmsman  chose, 
regardless  of  wind  and  weather.  Many  years 
elapsed  before  he  actually  began  to  work  out 
his  dreams,  and  then  he  met  with  failure  after 
failure.  He  believed  in  big  machines  and  the 
loss  of  one  of  his  airships  meant  the  waste  of 
a  large  sum  of  money,  but  he  persisted,  even 
though  he  spent  all  his  fortune,  and  had  to  go 
heavily  in  debt.  Every  one  thought  him  a  crank 
until  he  built  his  third  airship  and  proved  its 
worth  by  making  a  trip  of  270  miles.  At  once 


SHIPS  THAT  SAIL  THE  SKIES         155 

the  German  Government  was  interested  and  saw 
wonderful  military  possibilities  in  the  new  craft. 
The  Zeppelin  was  purchased  by  the  government 
and  money  was  given  the  inventor  to  further  his 
experiments. 

That  was  not  the  end  of  his  failures.  Before 
the  war  broke  out,  thirteen  Zeppelins  had  been 
destroyed  by  one  accident  or  another.  Evi- 
dently the  building  of  Zeppelin  airships  was  not 
a  paying  undertaking,  although  they  were  used 
to  carry  passengers  on  short  aerial  voyages. 
But  the  government  made  up  money  losses  and 
Zeppelin  went  on  developing  his  airships. 

Of  course,  he  was  not  the  only  one  to  build 
airships,  nor  even  the  first  -to  build  a  dirigible. 
The  French  built  some  large  dirigibles,  but 
they  failed  to  see  any  great  military  advantage 
in  ships  that  could  sail  through  the  air,  par- 
ticularly after  the  airplane  was  invented,  and 
so  it  happened  that  when  the  war  started  the 
French  were  devoting  virtually  all  their  ener- 
gies to  the  construction  of  speedy,  powerful 
airplanes.  As  for  the  British,  they  did  not  pay 
much  attention  to  airships.  The  idea  that  their 
isles  might  be  attacked  from  the  sky  seemed  an 
exceedingly  remote  possibility. 


156      INVENTIONS  OF  THE  GKEAT  WAR 

MOID,    SEMI-RIGID,    AND   FLEXIBLE   BALLOONS 

Count  Zeppelin  always  held  that  the  dirigible 
balloons  must  be  rigid,  so  that  they  could  be 
driven  through  the  air  readily  and  would  hold 
their  shape  despite  variations  in  the  pressure  of 
the  hydrogen.  The  French,  on  the  other  hand, 
used  a  semi-rigid  airship ;  that  is,  one  in  which  a 
flexible  balloon  is  attached  to  a  rigid  keel  or 
body.  The  British  clung  to  the  idea  of  an  en- 
tirely flexible  balloon  and  they  suspended  their 
car  from  the  gas-bag  without  any  rigid  frame- 
work to  hold  the  gas-bag  in  shape.  In  every 
case,  the  balloons  were  kept  taut  or  distended 
by  means  of  air-bags  or  ballonets.  These  air- 
bags  were  placed  inside  the  gas-bags  and  as  the 
hydrogen  expanded  it  would  force  the  air  out 
through  valves,  but  the  hydrogen  itself  would 
not  escape.  When  the  hydrogen  contracted,  the 
air-bags  were  pumped  full  of  air  so  as  to  main- 
tain the  balloon  in  its  fully  distended  condition. 
Additional  supplies  of  compressed  hydrogen 
were  kept  in  metal  tanks. 

In  the  Zeppelin  balloon,  however,  the  gas  was 
contained  in  separate  bags  which  were  placed  in 
a  framework  of  aluminum  covered  over  with 


(C)  Underwood  &  Underwood 

Giant  British  Dirigible  built  along  the  lines  of  a  Zeppelin 


(C)  Underwood  &  Underwood 

One  of  the  engine  cars  or  "power  eggs"  of  a  British  Dirigible 


SHIPS  THAT  SAIL  THE  SKIES          157 

fabric.  Count  Zeppelin  did  not  believe  in  plac- 
ing all  his  eggs  in  one  basket.  If  one  of  these 
balloons  burst  or  was  injured  in  any  way,  there 
was  enough  buoyancy  in  the  rest  of  the  gas-bags 
to  hold  up  the  airship.  As  the  Zeppelins  were 
enormous  structures,  the  framework  had  to  be 
made  strong  and  light,  and  it  was  built  up  of  a 
latticework  of  aluminum  alloy.  Aluminum  it- 
self was  not  strong  enough  for  the  purpose,  but 
a  mixture  of  aluminum  and  zinc  and  later  an- 
other alloy  known  as  duralumin,  consisting  of 
aluminum  with  three  per  cent  of  copper  and 
one  per  cent  of  nickel,  provided  a  very  rigid 
framework  that  was  exceedingly  light.  Dura- 
lumin is  four  or  five  times  as  strong  as  alum- 
inum and  yet  weighs  but  little  more. 

The  body  of  the  Zeppelin  is  not  a  perfect  cir- 
cle in  section,  but  is  made  up  in  the  form  of  a 
polygon  with  sixteen  sides,  and  the  largest  of  the 
Zeppelins  used  during  the  war  contained  sixteen 
compartments,  in  each  of  which  was  placed  a 
large  hydrogen  gas-bag.  A  super-Zeppelin,  as 
the  latest  type  is  called,  was  about  seventy-five 
feet  in  diameter  and  seven  hundred  and  sixty 
feet  long,  or  almost  as  long  as  three  New 
York  street  blocks.  In  its  gas-bags  it  carried 


158      INVENTIONS  OF  THE  GREAT  WAR 

two  million  cubic  feet  of  hydrogen  and  although 
the  whole  machine  with  its  fuel,  stores,  and  pas- 
sengers weighed  close  to  fifty  tons,  it  was  so 
much  lighter  than  the  air  it  displaced  that  it 
had  a  reserve  buoyancy  of  over  ten  tons. 

KEEPING  ENGINES  CLEAB  OF  THE  INFLAMMABLE 
HYDROGEN 

As  hydrogen  is  a  very  inflammable  gas,  it  is 
extremely  dangerous  to  have  an  internal-com- 
bustion engine  operating  very  near  the  gas- 
bags. In  the  super-Zeppelins  the  engines  were 
placed  in  four  cars  suspended  from  the  balloon. 
There  was  one  of  these  cars  forward,  and  one 
at  the  stern,  while  near  the  center  were  two  cars 
side  by  side.  In  the  rear  car  there  were  two 
engines,  either  of  which  could  be  used  to  drive 
the  propeller.  By  means  of  large  steering  rud- 
ders and  horizontal  rudders,  the  machine  could 
be  forced  to  dive  or  rise  or  turn  in  either  direc- 
tion laterally.  The  pilot  of  the  Zeppelin  had 
an  elaborate  operating-compartment  from 
which  he  could  control  the  rudders,  and  he  also 
had  control  of  the  valves  in  the  ballonets  so  that 
by  the  touch  of  a  button  he  could  regulate  the 
pressure  of  gas  in  any  part  of  the  dirigible. 


SHIPS  THAT  SAIL  THE  SKIES 

There  were  nineteen  men  in  the  crew  of  the 
Zeppelin — two  in  the  operating-compartment, 
and  two  in  each  of  the  cars  containing  engines, 
except  for  the  one  at  the  stern  in  which  there 
were  three  men.  The  other  men  were  placed 
in  what  was  known  as  the  "cat  walk"  or  pass- 
ageway running  inside  the  framework  under 
the  gas-bags.  These  men  were  given  various 
tasks  and  were  supposed  to  get  as  much  sleep 
as  they  could,  so  as  to  be  ready  to  replace  the 
other  men  at  need. 

The  engine  cars  at  each  side  of  the  balloon 
were  known  as  power  eggs  because  of  their  gen- 
eral egg  shape.  At  the  center  of  the  Zeppelin 
the  bombs  were  stored,  and  there  were  electro- 
magnetic releasing-devices  operated  from  the 
pilot's  room  by  which  the  pilot  could  drop  the 
bombs  whenever  he  chose.  The  Zeppelin  also 
carried  machine-guns  to  fight  off  airplanes. 
Gasolene  was  stored  in  tanks  which  were  placed 
in  various  parts  of  the  machine,  any  one  of 
which  could  feed  one  or  all  of  the  engines,  and 
they  were  so  arranged  that  they  could  be  thrown 
overboard  when  the  gasolene  was  used  up,  so 
as  to  lighten  the  load  of  the  Zeppelin.  Water 
ballast  was  used  instead  of  sand,  and  alcohol 


160      INVENTIONS  OF  THE  GREAT  WAR 

was  mixed  with  the  water  to  keep  it  from  freez- 
ing. The  machine  which  came  down  in  French 
territory  and  was  captured  before  it  could  be 
destroyed  by  the  pilot,  found  itself  unable  to 
rise  because  in  the  intense  cold  of  the  upper 
air  the  water  ballast  had  frozen,  and  it  could 
not  be  let  out  to  lighten  the  load  of  the  Zep- 
pelin. 

THE  ZEPPELIN'S  TINY  ANTAGONISTS 

The  one  thing  above  all  others  that  the  Zep- 
pelin commander  feared  was  the  attack  of  air- 
planes. In  the  early  stages  of  the  war,  it  was 
considered  unsafe  for  airplanes  to  fly  by  night 
because  of  the  difficulty  of  making  a  landing  in 
the  dark.  Later  this  difficulty  was  overcome  by 
the  use  of  search-lights  at  the  landing-fields. 
The  airplane  would  signal  its  desire  to  land  and 
the  search-lights  would  point  out  the  proper 
landing-field  for  it.  So  that  after  the  first  few 
months  of  the  war  Zeppelins  were  subjected  to 
the  danger  of  airplane  attack.  Of  course,  on  a 
dark  night  it  was  very  difficult  for  an  airplane 
to  locate  a  Zeppelin,  because  the  huge  machine 
could  not  be  seen  and  the  throb  of  its  engines 
was  drowned  out  by  the  engines  of  the  airplane 


SHIPS  THAT  SAIL  THE  SKIES         161 

itself.    Nevertheless,     Zeppelins     were     occa- 
sionally located  and  destroyed  by  airplanes. 

The  danger  of  the  Zeppelin  lay  in  the  fact 
that  it  was  supported  by  an  enormous  volume 
of  very  inflammable  gas  and  the  airplane  needed 
but  to  set  fire  to  this  gas  to  cause  the  destruc- 
tion of  the  giant  of  the  air.  And  so  the  ma- 
chine-guns carried  by  airplanes  were  provided 
with  explosive,  flaming  bullets.  A  burst  of 
flame  within  the  gas-bag  would  not  set  the  gas 
on  fire,  because  there  would  be  no  air  inside 
to  feed  the  fire,  but  surrounding  the  gas-bag 
there  was  always  a  certain  leakage  of  hydro- 
gen which  would  mix  with  the  air  in  the  com- 
partment and  this  would  produce  an  explosive 
mixture  which  needed  but  the  touch  of  fire  to 
set  it  off.  The  Zeppelin  wras  provided  with  a 
ventilating-system  to  carry  off  these  explosive 
gases,  but  they  could  never  be  disposed  of  very 
effectively,  and,  as  a  consequence,  a  number  of 
Zeppelins  were  destroyed  by  the  tiny  antagon- 
ists that  were  sent  up  by  the  British  and  the 
French.  To  fight  off  these  assailants  the  Ger- 
mans provided  their  Zeppelins  with  guns  which 
would  fire  shrapnel  shell.  It  is  difficult  for  a 
Zeppelin  to  use  machine-guns  against  an  air- 


162      INVENTIONS  OF  THE  GREAT  WAR 

plane  because  the  latter  would  merely  climb 
above  the  Zeppelin  and  would  be  shielded  by 
the  balloon  itself.  And  so  the  Germans  put  a 
gun  emplacement  on  top  of  the  balloon  both 
forward  and  aft.  There  was  a  deck  extending 
along  the  top  of  the  balloon  which  was  reached 
by  a  ladder  running  up  through  the  center  of 
the  airship.  But  it  was  impossible  to  ward  off 
the  fleet  little  antagonists,  once  the  dirigible  wa-s 
discovered.  True,  a  Zeppelin  could  make  as 
much  as  seventy  miles  per  hour,  but  the  fast- 
est airplanes  could  travel  twice  as  fast  as  that. 

SUSPENDING   AN    OBSERVER   BELOW    THE   ZEPPELIN 

One  ingenious  scheme  that  was  tried  was  to 
suspend  an  observation  car  under  the  Zeppelin. 
The  car  was  about  fourteen  feet  long  and  five 
feet  in  diameter,  fitted  with  a  tail  to  keep  it 
headed  in  the  direction  it  was  towed.  It  had 
glass  windows  forward  and  there  was  plenty  of 
room  in  it  for  a  man  to  lie  at  full  length  and 
make  observations  of  things  below.  The  car 
with  its  observer  could  be  lowered  a  few  thou- 
sand feet  below  the  Zeppelin,  so  that  the  ob- 
server could  watch  proceedings  below,  while  the 
airship  remained  hidden  among  the  clouds. 


SHIPS  THAT  SAIL  THE  SKIES         163 

The  observer  was  connected  by  telephone  with 
the  chart-room  of  the  Zeppelin  and  could  report 
his  discoveries  or  even  act  as  a  pilot  to  direct 
the  course  of  the  ship. 

But  despite  everything  that  could  be  done, 
the  Zeppelin  eventually  proved  a  failure  as  a 
war-vessel  because  it  was  so  very  costly  to  con- 
struct and  operate  and  could  so  easily  be  de- 
stroyed, and  the  Germans  began  to  build  huge 
airplanes  with  which  bombing-raids  could  be 
continued. 

Strange  to  say,  however,  although  the  Ger- 
mans were  ready  to  admit  the  failure  of  their 
big  airship,  when  the  war  stopped  the  Allies 
were  actually  building  machines  patterned  after 
the  Zeppelin,  but  even  larger,  and  expected  to 
use  them  for  bombing-excursions  over  Ger- 
many. This  astonishing  turn  of  the  tables  was 
due  to  the  fact  that  America  had  made  a  con- 
tribution to  aeronautics  that  solved  the  one 
chief  drawback  of  the  Zeppelin. 

A   BALLOON    GAS    THAT    WILL  NOT   BURN 

When  we  entered  the  war  against  Germany, 
our  allies  placed  before  us  all  their  problems 
and  among  them  was  this  one  of  the  highly  in- 


164      INVENTIONS  OP  THE  GREAT  WAR 

flammable  airship.  Could  we  not  furnish  a  sub- 
stitute for  hydrogen  that  would  not  burn?  It 
was  suggested  to  us  that  helium  would  do  if  we 
could  produce  thai  gas  cheaply  and  in  sufficient 
quantity.  Now,  helium  has  a  history  of  its  own 
that  is  exceedingly  interesting. 

Every  now  and  then  the  moon  bobs  its  head 
into  our  light  and  we  have  a  solar  eclipse.  But 
our  satellite  is  not  big  enough  to  cut  off  all 
the  light  of  the  big  luminary  and  the  fiery  at- 
mosphere of  the  sun  shows  us  a  brilliant  halo 
all  around  the  black  disk  of  the  moon.  Long 
ago,  astronomers  analyzed  this  flaming  atmos- 
phere with  the  spectroscope,  and  by  the  differ- 
ent bands  of  light  that  appeared  they  were  able 
to  determine  what  gases  were  present  in  the 
sun's  atmosphere.  But  there  was  one  band  of 
bright  yellow  which  they  could  not  identify. 
Evidently  this  was  produced  by  a  gas  unknown 
on  earth,  and  they  called  it  "helium"  or  "sun" 
gas. 

For  a  quarter  of  a  century  this  sun  gas  re- 
mained a  mystery;  then  one  day,  in  1895,  Sir 
William  Ramsay  discovered  the  same  band  of 
light  when  studying  the  spectrum  of  the  mineral 
cleveite.  The  fact  that  astronomers  had  been 


SHIPS  THAT  SAIL  THE  SKIES         165 

able  to  single  out  an  element  on  the  sun  ninety 
million  miles  away  before  our  chemists  could 
find  it  right  here  on  earth,  produced  a  mild  sen- 
sation, but  the  general  public  attached  no  spe- 
cial importance  to  the  gas  itself.  It  proved 
to  be  a  very  light  substance,  next  to  hydrogen 
the  lightest  of  gases,  and  for  years  it  resisted 
all  attempts  at  liquefaction.  Only  when  Onnes, 
the  Dutch  scientist,  succeeded  in  getting  it  down 
to  a  temperature  of  450  degrees  below  zero,  Fah- 
renheit, did  the  gas  yield  to  the  chill  and  con- 
dense into  a  liquid.  The  gas  would  not  burn; 
it  would  not  combine  with  any  other  elements, 
and  apparently  it  had  no  use  on  earth,  and  it 
might  have  remained  indefinitely  a  lazy  member 
of  the  chemical  fraternity  had  not  the  great 
world  conflict  stirred  us  into  frenzied  activity 
in  all  branches  of  science  in  our  effort  to  beat 
the  Hun. 

Because  the  gas  had  no  commercial  value, 
there  was  only  a  small  amount  of  helium  to  be 
found  in  the  whole  world.  Not  a  single  labora- 
tory in  the  United  States  had  more  than  five 
cubic  feet  of  it  and  its  price  ranged  from 
$1,500  to  $6,000  per  cubic  foot.  At  the  lowest 
price  it  would  cost  $3,000,000,000  to  provide  gas 


166      INVENTIONS  OP  THE  GREAT  WAR 

enough  for  one  airship  of  Zeppelin  dimensions 
and  it  seemed  absurd  even  to  think  of  a  helium 
airship. 

AMERICAN    CHEMISTS    TO    THE   RESCUE 

Just  before  the  war  it  was  discovered  that 
there  is  a  considerable  amount  of  helium  in  the 
natural  gas  of  Oklahoma,  Texas,  and  Kansas, 
and  Sir  William  Ramsey  suggested  that  our 
chemists  might  study  some  method  of  getting 
helium  from  this  source.  The  only  way  of  sep- 
arating it  out  was  to  liquefy  the  gases  by  sub- 
jecting them  to  extreme  cold.  All  gases  turn 
to  liquid  if  they  are  cooled  sufficiently,  and  then 
further  cold  will  freeze  them  solid.  But  helium 
can  stand  more  cold  than  any  other  and  this 
fact  gave  the  clue  to  its  recovery  from  natu- 
ral gas.  The  latter  was  frozen  and  one  after 
another  the  different  elements  condensed  into 
liquid,  until  finally  only  helium  was  left. 
This  sounds  simple,  but  it  is  a  difficult  mat- 
ter to  get  such  low  temperature  as  that  on  a 
large  scale  and  do  it  economically.  To  be  of 
any  real  service  in  aeronautics  helium  would 
have  to  be  reduced  in  cost  from  fifteen  hun- 
dred dollars  to  less  than  ten  cents  per  cubic 


SHIPS  THAT  SAIL  THE  SKIES         167 

foot.  Several  different  kinds  of  refrigerating- 
machinery  were  tried  and  finally  just  before  the 
war  was  brought  to  a  close  by  the  armistice  we 
had  succeeded  in  producing  helium  at  the  rate 
of  eight  cents  per  cubic  foot,  with  the  prospect 
of  reducing  its  cost  still  further.  A  large  plant 
for  recovering  helium  was  being  built.  The 
plant  will  have  been  completed  before  this  book 
is  published,  and  it  will  be  turning  out  helium 
for  peaceful  instead  of  military  airships. 

The  reduction  in  the  cost  of  helium  is  really 
one  of  the  most  important  developments  of  this 
war.  By  removing  the  fire  risk  from  airships 
we  can  safely  use  these  craft  for  aerial  cruises 
or  for  quick  long-distance  travel  over  land  and 
sea.  For,  even  in  time  of  peace,  sailing  under 
millions  of  cubic  feet  of  hydrogen  is  a  serious 
matter.  Although  no  incendiary  bullets  are  to 
be  feared,  there  is  always  the  danger  of  setting 
fire  to  the  gas  within  the  exhaust  of  the  engines. 
Engines  have  had  to  be  hung  in  cars  well  below 
the  balloon  proper.  But  with  helium  in  the  gas- 
bags the  engines  can  be  placed  inside  the  bal- 
loon envelop  and  the  propellers  can  operate  on 
the  center  line  of  the  car. 

In  the  case  of  one  Zeppelin,  the  hydrogen  was 


168      INVENTIONS  OF  THE  GREAT  WAR 

set  on  fire  by  an  electric  spark  produced  by  fric- 
tion on  the  fabric  of  one  of  the  gas-bags,  and  so 
even  with  the  engine  exhausts  properly  screened 
there  is  danger.  The  helium  airship,  however, 
would  be  perfectly  safe  from  fire  and  passen- 
gers could  smoke  on  deck  or  in  their  cabins 
within  the  balloon  itself  without  any  more  fear 
of  fire  than  they  would  have  on  shipboard. 
Wonderful  possibilities  have  been  opened  by  the 
production  of  helium  on  a  large  and  economical 
scale,  and  the  airship  seems  destined  to  play 
an  important  part  in  transportation  very  soon. 
As  this  book  is  going  to  press,  we  learn  of  enor- 
mous dirigibles  about  to  be  built  in  England  for 
passenger  service,  which  will  have  half  again  as 
great  a  lifting-power  as  the  largest  Zeppelins. 
The  final  chapter  of  the  story  of  dirigibles  is  yet 
to  be  written,  but  in  concluding  this  chapter  it 
is  interesting  to  note  that  the  world's  greatest 
aeronautic  expert  got  his  first  inspiration  from 
America  and  finally  that  America  has  now  fur- 
nished the  one  element  which  was  lacking  to 
make  the  dirigible  balloon  a  real  success. 


CHAPTER  IX 
GETTING  THE  RANGE 

EVERY  person  with  a  good  pair  of  eyes  in 
his  head  is  a  range-finder.     He  may  not 
know  it,  but  he  is,  just  the  same,  and  the  way  to 
prove  it  is  to  try  a  little  range-finding  on  a  small 
scale. 

Use  the  top  of  a  table  for  your  field  of  opera- 
tions, and  pick  out  some  spot  within  easy  reach 
of  your  hand  for  the  target  whose  range  you 
wish  to  find.  The  target  may  be  a  penny  or  a 
small  circle  drawn  on  a  piece  of  white  paper. 
Take  a  pencil  in  your  hand  and  imagine  it  is 
a  shell  which  you  are  going  to  land  on  the 
target.  It  is  not  quite  fair  to  have  a  bird's-eye 
view  of  the  field,  so  get  down  -on  your  knees  and 
bring  your  eyes  within  a  few  inches  of  the  top 
of  the  table.  Now  close  one  eye  and  making 
your  hand  describe  an  arc  through  the  air,  like 
the  arc  that  a  shell  would  describe,  see  how 
nearly  you  can  bring  the  pencil-point  down  on 

169 


170      INVENTIONS  OP  THE  GREAT  WAR 

the  center  of  the  target.  Do  it  slowly,  so  that 
your  eye  may  guide  the  hand  throughout  its 
course.  You  will  be  surprised  to  find  out  how 
far  you  come  short,  or  overreach  the  mark. 
You  will  have  actually  to  grope  for  the  target. 
If  by  any  chance  you  should  score  a  hit  on  the 
first  try,  you  may  be  sure  that  it  is  an  accident. 

Have  a  friend  move  the  target  around  to  a 
different  position,  and  try  again.  Evidently, 
with  one  eye  you  are  not  a  good  range-finder; 
but  now  use  two  eyes  and  you  will  score  a  hit 
every  time.  Not  only  can  you  land  the  pencil 
on  the  penny,  but  you  will  be  able  to  bring  it 
down  on  the  very  center  of  the  target. 

The  explanation  of  this  is.  that  when  you 
bring  your  eyes  to  bear  upon  any  object  that 
is  near  by,  they  have  to  be  turned  in  slightly,  so 
that  both  of  them  shall  be  aimed  directly  at 
that  object.  The  nearer  the  object,  the  more 
they  are  turned  in,  and  the  farther  the  object, 
the  more  nearly  parallel  are  the  eyes.  Long 
experience  has  taught  you  to  gage  the  distance 
of  an  object  by  the  feel  of  the  eyes— that  is,  by 
the  effort  your  muscles  have  to  make  to  pull 
the  eyes  to  a  focus — and  in  this  way  the  eyes 
give  you  the  range  of  an  object.  You  do  not 


GETTING  THE  RANGE  171 

know  what  the  distance  is  in  feet  or  inches,  but 
you  can  tell  when  the  pencil-point  has  moved 
out  until  it  is  at  the  same  focus  as  the  target. 
The  experiment  can  be  tried  on  a  larger  scale 
with  the  end  of  a  fishing-rod,  but  here  you  will 
probably  have  to  use  a  larger  target.  However, 
there  is  a  limit  to  which  you  can  gage  the  range. 
At  a  distance  of,  say,  fifteen  or  twenty  feet,  a 
variation  of  a  few  inches  beyond  or  this  side 
of  the  target  makes  scarcely  any  change  in  the 
focus  of  the  eyes.  That  is  because  the  eyes  are 
so  close  together.  If  they  were  farther  apart, 
they  could  tell  the  range  at  much  greater  dis- 
tances. 

SPREADING  THE  EYES  FAE  APART 

Now  the  ordinary  range-finder,  used  in  the 
army  and  in  the  navy,  is  an  arrangement  for 
spreading  the  eyes  apart  to  a  considerable  dis- 
tance. Of  course  the  -eyes  are  not  actually 
spread,  but  their  vision  is.  The  range-finder  is 
really  a  double  telescope.  The  barrel  is  not 
pointed  at  an  object,  but  it  is  held  at  right  angles 
to  it.  You  look  into  the  instrument  at  the  mid- 
dle of  the  barrel  and  out  of  it  at  the  two  ends. 
A  system  of  mirrors  or  prisms  makes  this  pos- 


172      INVENTIONS  OF  THE  GREAT  WAR 

sible.  The  range-finder  may  be  a  yard  or  more 
in  length,  which  is  equivalent  to  spreading  your 
eyes  a  yard  or  more  apart.  Now,  the  prisms  or 
object-glasses  at  the  ends  of  the  tube  are  ad- 
justable, so  that  they  will  turn  in  until  they 
focus  directly  on  the  target  whose  range  you 
wish  to  find,  and  the  angle  through  which  these 
glasses  are  turned  gives  a  measure  of  the  dis- 
tance of  the  target.  The  whole  thing  is  cal- 
culated out  so  that  the  distance  in  feet,  yards, 
or  meters,  or  whatever  the  measure  may  be,  is 
registered  on  a  scale  in  the  range-finder.  Ordi- 
narily only  one  eye  is  used  to  look  through  the 
range-finder,  because  the  system  of  mirrors  is 
set  to  divide  the  sight  of  that  one  eye  and  make 
it  serve  the  purposes  of  two.  That  leaves  the 
other  eye  free  to  read  the  scale,  which  comes 
automatically  into  view  as  the  range-finder  is 
adjusted  for  the  different  ranges. 

On  the  battle-ships  enormous  range-finders 
are  used.  Some  of  them  are  twenty  feet  long. 
With  the  eyes  spread  as  far  apart  as  that  and 
with  a  microscope  to  read  the  scale,  you  can 
imagine  how  accurately  the  range  can  be  found, 
even  when  the  target  is  miles  away.  But  on 
land  such  big  range-finders  cannot  conveniently 


GETTING  THE  RANGE  173 

be  used;  they  are  too  bulky.  When  it  is  neces- 
sary to  get  the  range  of  a  very  distant  object, 
two  observers  are  used  who  are  stationed  sev- 
eral hundred  yards  apart.  These  observers 
have  telescopes  which  they  bear  upon  the  ob- 
ject, and  the  angle  through  which  they  have  to 
turn  the  telescope  is  reported  by  telephone  to 
the  battery,  where,  by  a  rapid  calculation,  it  is 
possible  to  estimate  the  exact  position  of  the 
target.  Then  the  gun  is  moved  up  or  down,  to 
the  right  or  to  the  left,  according  to  the  cal- 
culation. The  observers  have  to  creep  as  near 
to  the  enemy  as  possible  and  they  must  be  up 
high  enough  to  command  a  good  view  of  the 
target.  Sometimes  they  are  placed  on  top  of 
telegraph  poles  or  hidden  up  a  tall  tree,  or  in 
a  church  steeple. 

GETTING   THE   OBSERVER   OFF   THE   GROUND 

This  was  the  method  of  getting  the  range  in 
previous  wars  and  it  was  used  to  a  considerable 
extent  in  the  war  we  have  just  been  through. 
But  the  great  European  conflict  brought  out 
wonderful  improvements  in  all  branches  of 
fighting ;  and  range-finding  was  absolutely  rev- 
olutionized, because  shelling  was  done  at  greater 


174      INVENTIONS  OF  THE  GREAT  WAR 

ranges  than  ever  before,  but  chiefly  because  the 
war  was  carried  up  into  the  sky. 

A  bird's-eye  observation  is  much  more  ac- 
curate than  any  that  can  be  obtained  from  the 
ground.  Even  before  this  war,  some  observa- 
tions were  taken  by  sending  a  man  up  in  a  kite, 
particularly  a  kite  towed  from  a  ship,  and  even 
as  far  back  as  the  Civil  War  captive  balloons 
were  used  to  raise  an  observer  to  a  good  height 
above  the  ground.  They  were  the  ordinary 
round  balloons,  but  the  observation  balloon  of 
to-day  is  a  very  different-looking  object.  It  is 
a  sausage-shaped  gas-bag  that  is  held  on  a  slant 
to  the  wind  like  a  kite,  so  that  the  wind  helps 
to  hold  it  up.  To  keep  it  head-on  to  the  wind, 
there  is  a  big  air-bag  that  curls  around  the 
lower  end  of  the  sausage.  This  acts  like  a  rud- 
der, and  steadies  the  balloon.  Some  balloons 
have  a  tail  consisting  of  a  series  of  cone-shaped 
cups  strung  on  a  cable.  A  kite  balloon  will  ride 
steadily  in  a  wind  that  would  dash  a  common 
round  balloon  in  all  directions.  Observers  in 
these  kite  balloons  are  provided  with  telephone 
instruments  by  which  they  can  communicate  in- 
stantly with  the  battery  whose  fire  they  are  di- 
recting. But  a  kite  balloon  is  a  helpless  object; 


GETTING  THE  RANGE  175 

it  cannot  fight  the  enemy.  The  hydrogen  gas 
that  holds  it  up  will  burn  furiously  if  set  on 
fire.  In  the  war  an  enemy  airplane  had  merely 
to  drop  a  bomb  upon  it  or  fire  an  incendiary  bul- 
let into  it,  and  the  balloon  would  go  up  in  smoke. 
Nothing  could  save  it,  once  it  took  fire,  and  all 
the  observers  could  do  was  to  jump  for  their 
lives  as  soon  as  they  saw  the  enemy  close  by. 
They  always  had  parachutes  strapped  to  them, 
so  they  could  leap  without  an  instant 's  delay  in 
case  of  sudden  danger.  At  the  very  first  ap- 
proach of  an  enemy  airplane,  the  kite  balloon 
had  to  be  hauled  down  or  it  would  surely  be  de- 
stroyed, and  so  kite  balloons  were  not  very  de- 
pendable observation  stations  for  the  side 
which  did  not  control  the  air. 

As  stated  in  the  preceding  chapter,  just  be- 
fore the  fighting  came  to  an  end,  our  army  was 
preparing  to  use  balloons  that  were  not  afraid 
of  flaming  bullets,  because  they  were  to  be  filled 
with  a  gas  that  would  not  burn. 

MAKING   MAPS   WITH   A    CAMERA 

Because  airplanes  filled  the  sky  with  eyes, 
everything  that  the  army  did  near  the  front 
had  to  be  carefully  hidden  from  the  winged 


176      INVENTIONS  OF  THE  GREAT  WAR 

scouts.  Batteries  were  concealed  in  the  woods, 
or  under  canopies  where  the  woods  were  shot 
to  pieces,  or  they  were  placed  in  dugouts  so  that 
they  could  not  be  located.  Such  targets  could 
seldom  be  found  with  a  kite  balloon.  It  was 
the  task  of  airplane  observers  to  search  out 
these  hidden  batteries.  The  eye  alone  was  not 
depended  upon  to  find  them.  Large  cameras 
were  used  with  telescopic  lenses  which  would 
bring  the  surface  of  the  earth  near  while  the 
airplane  flew  at  a  safe  height.  These  were 
often  motion-picture  cameras  which  would  auto- 
matically make  an  exposure  every  second,  or 
every  few  seconds. 

When  the  machine  returned  from  a  photo- 
graphing-expedition, the  films  were  developed 
and  printed,  and  then  pieced  together  to  form  a 
photographic  map.  The  map  was  scrutinized 
very  carefully  for  any  evidence  of  a  hidden  bat- 
tery or  for  any  suspicious  enemy  object.  As 
the  enemy  was  always  careful  to  disguise  its 
work,  the  camera  had  to  be  fitted  with  color- 
screens  which  would  enable  it  to  pick  out  de- 
tails that  would  not  be  evident  to  the  eye.  As 
new  photographic  maps  were  made  from  day  to 
day,  they  were  carefully  compared  one  with 


GETTING  THE  RANGE  177 

the  other  so  that  it  might  be  seen  if  there  was  the 
slightest  change  in  them  which  would  indicate 
some  enemy  activity.  As  soon  as  a  suspicious 
spot  was  discovered,  its  position  was  noted  on 
a  large-scale  military  map  and  the  guns  were 
trained  upon  it. 

CORRECTING   THE   AIM 

It  is  one  thing  to  know  where  the  target  is  and 
another  to  get  the  shell  to  drop  upon  it.  In  the 
firing  of  a  shell  a  distance  of  ten  or  twenty  miles, 
the  slightest  variation  in  the  gun  will  make  a 
difference  of  many  yards  in  the  point  where  the 
shell  lands.  Not  only  that,  but  the  direction  of 
the  wind  and  the  density  of  the  air  have  a  part 
to  play  in  the  journey  of  the  shell.  If  the  shell 
traveled  through  a  vacuum,  it  would  be  a  much 
simpler  matter  to  score  a  hit  by  the  map  alone. 
But  even  then  there  would  be  some  differences, 
because  a  gun  has  to  be  " warmed  up"  before  it 
will  fire  according  to  calculation.  That  is  why 
it  is  necessary  to  have  observers,  or  "  spotters " 
as  they  are  called,  to  see  where  the  shell  actu- 
ally do  land  and  tell  the  gun-pointers  whether 
to  elevate  or  depress  the  gun,  and  how  much  to 
"traverse"  it — that  is,  move  it  sideways.  This 


178      INVENTIONS  OF  THE  GREAT  WAR 

would  not  be  a  very  difficult  matter  if  there 
were  only  one  gun  firing,  but  when  a  large  num- 
ber of  guns  are  being  used,  as  was  almost  in- 
variably the  case  in  the  war,  the  spotter  had  to 
know  which  shell  belonged  to  -the  gun  he  was 
directing. 

One  of  the  most  important  inventions  of  the 
war  was  the  wireless  telephone,  which  airplanes 
used  and  which  were  brought  to  such  perfection 
that  the  pilot  of  an  airplane  could  talk  to  a 
station  on  the  earth  without  any  difficulty, 
from  a  distance  of  ten  miles;  and  in  some 
cases  he  could  reach  a  range  of  fifty  miles. 
With  the  wireless  telephone,  the  observer  could 
communicate  instantly  with  the  gun-pointer, 
and  tell  him  when  to  fire.  Usually  -thirty  sec- 
onds were  allowed  after  the  signal  sent  by  the 
observer  before  the  gun  was  fired,  and  on  the  in- 
stant of  firing,  a  signal  was  sent  to  the  man  in 
the  airplane  to  be  on  the  lookout  for  the  shell. 
Knowing  the  position  of  the  target,  the  gun- 
pointer  would  know  how  long  it  would  take  the 
shell  to  travel  through  the  air,  and  he  would 
keep  the  man  in  the  airplane  posted,  warning 
him  at  ten  seconds,  five  seconds,  and  so  forth, 
before  the  shell  was  due  to  land. 


GETTING  THE  RANGE  179 

In  order  to  keep  the  eyes  fresh  for  observation 
and  not  to  have  them  distracted  by  other  sights, 
the  observer  usually  gazed  into  space  until  just 
before  the  instant  the  shell  was  to  land.  Then 
he  would  look  for  the  column  of  smoke  pro- 
duced by  the  explosion  of  the  shell  and  report 
back  to  the  battery  how  far  wide  of  the  mark 
the  shell  had  landed.  A  number  of  shell  would 
be  fired  at  regular  intervals,  say  four  or  five  per 
minute,  so  that  the  observer  would  know  which 
shell  belonged  to  the  gun  in  question. 

There  are  different  kinds  of  shell.  Some 
will  explode  on  the  instant  of  contact  with  the 
earth.  These  are  meant  to  spread  destruction 
over  the  surface.  There  are  other  shell  which 
will  explode  a  little  more  slowly  and  these  pene- 
trate the  ground  to  some  extent  before  going  off ; 
while  a  third  type  has  a  delayed  action  and  is 
intended  to  be  buried  de^ep  in  the  ground  before 
exploding,  so  as  to  destroy  dugouts  and  under- 
ground positions.  The  bursts  of  smoke  from 
the  delayed-action  "shell  and  the  semi-delayed- 
action  shell  rise  in  a  slender  vertical  column  and 
are  not  so  easily  seen  from  the  sky.  The  instan- 
taneous shell,  however,  produces  a  broad  burst 
of  smoke  which  can  be  spotted  much  more 


180      INVENTIONS  OF  THE  GREAT  WAR 

readily,  and  this  enables  the  man  in  the  air- 
plane to  determine  the  position  of  the  shell  with 
greater  accuracy.  For  this  reason,  instantan- 
eous shell  were  usually  used  for  spotting-pur- 
poses,  and  after  the  gun  had  found  its  target, 
other  shell  were  used  suited  to  the  character  of 
the  work  that  was  to  be  done. 

MINIATURE    BATTLE-FIELDS 

Observation  of  shell-fire  from  an  airplane 
called  for  a  great  deal  of  experience,  and  our 
spotters  were  given  training  on  a  miniature 
scale  before  they  undertook  to  do  spotting  from 
the  air.  A  scaffolding  was  erected  in  the  train- 
ing-quarters over  a  large  picture  of  a  typical  bit 
of  enemy  territory.  Men  were  posted  at  the 
top  of  this  scaffolding  so  that  they  could  get  a 
bird's-eye  view  of  the  territory  represented  on 
the  map,  and  they  were  connected  by  telephone 
or  telegraph  with  men  below  who  represented 
the  batteries.  The  instructor  would  flash  a  little 
electric  light  here  and  there  on  the  miniature 
battle-field,  and  the  observers  had  to  locate  these 
flashes  and  tell  instantly  how  far  they  were 
from  certain  targets.  This  taught  them  to  be 
keen  and  quick  and  to  judge  distance  accurately. 


GETTING  THE  RANGE  181 

Airplane  observing  was  difficult  and  dangerous, 
and  often  impossible.  On  cloudy  days  the  ob- 
server might  be  unable  to  fly  at  a  safe  height 
without  being  lost  in  the  clouds.  Then  depend- 
ence had  to  be  placed  upon  observers  stationed 
at  vantage-points  near  the  enemy,  or  in  kite 
balloons. 

SPOTTING   BY   SOUND 

When  there  is  no  way  of  seeing  the  work  of 
a  gun,  it  is  still  possible  to  correct  the  aim,  be- 
cause the  shell  can  be  made  to  do  its  own  spot- 
ting. Every  time  a  shell  lands,  it  immediately 
announces  the  fact  with  a  loud  report.  That 
report  is  really  a  message  which  the  shell  sends 
out  in  all  directions  with  a  speed  of  nearly  800 
miles  per  hour — 1,142  feet  per  second,  to  be 
exact.  This  sound-message  is  picked  up  by  a 
recorder  at  several  different  receiving-stations. 
Of  course  it  reaches  the  nearest  station  a  frac- 
tion of  a  second  before  it  arrives  at  the  next 
nearest  one.  The  distance  of  each  station  from 
the 'target  is  known  by  careful  measurement  on 
the  map,  and  the  time  it  takes  for  sound  to 
travel  from  the  target  to  each  station  is  accur- 
ately worked  out.  If  the  sound  arrives  at  each 


182      INVENTIONS  OF  THE  GREAT  WAR 

station  on  schedule  time,  the  shell  has  scored  a 
hit ;  but  if  it  reaches  one  station  a  trifle  ahead 
of  time  and  lags  behind  at  another,  that  is  evi- 
dence that  the  shell  has  missed  the  target  and  a 
careful  measure  of  the  distance  in  time  shows 
how  far  and  in  what  direction  it  is  wide  of  the 
mark.  In  this  way  it  was  possible  to  come 
within  fifty  or  even  twenty-five  yards  of  the 
target. 

This  sound-method  was  also  used  to  locate 
an  enemy  battery.  It  was  often  well  nigh  im- 
possible to  locate  a  battery  in  any  other  way. 
With  the  use  of  smokeless  powder,  there  is 
nothing  to  betray  the  position  of  the  gun,  ex- 
cept the  flash  at  the  instant  of  discharge,  and 
even  the  flash  was  hidden  by  screens  from  the 
view  of  an  airplane.  Aside  from  this,  when  an 
airplane  came  near  enough  actually  to  see  one 
of  these  guns,  the  gun  would  stop  firing  until  the 
airplane  had  been  driven  off.  But  a  big  gun 
has  a  big  voice,  and  it  is  impossible  to  silence 
it.  Often  a  gun  whose  position  has  remained 
a  secret  for  a  long  time  was  discovered  because 
the  gun  itself  "  peached. " 

The  main  trouble  with  sound-spotting  was 
that  there  were  usually  so  many  shell  and  guns 


GETTING  THE  RANGE  183 

going  off  at  the  same  time  that  it  was  difficult 
if  not  impossible  to  distinguish  one  from  an- 
other. Sometimes  the  voice  of  a  hidden  gun 
was  purposely  drowned  by  the  noise  of  a  lot  of 
other  guns.  After  all,  the  main  responsibility 
for  good  shooting  had  to  fall  on  observers  who 
could  actually  see  the  target,  and  when  we  think 
of  the  splendid  work  of  our  soldiers  in  the  war, 
we  must  not  forget  to  give  full  credit  to  the 
tireless  men  whose  duty  it  was  to  watch,  to 
the  men  on  wings  who  dared  the  fierce  battle- 
planes of  the  enemy,  to  the  men  afloat  high  in 
the  sky  who  must  leap  at  a  moment's  notice 
from  under  a  blazing  mass  of  hydrogen,  and 
finally  to  the  men  who  crept  out  to  perilous 
vantage-points  at  risk  of  instant  death,  in  order 
to  make  the  fire  of  their  batteries  tell. 


CHAPTER  X 
TALKING  IN  THE  SKY 

IN  one  field  of  war  invention  the  United  States 
held  almost  a  monopoly  and  the  progress 
Americans  achieved  was  epoch-making. 

Before  the  war,  an  aviator  when  on  the  wing 
was  both  deaf  and  dumb.  He  could  communi- 
cate with  other  airplanes  or  with  the  ground 
only  by  signal  or,  for  short  distances,  by  radio- 
telegraphy,  but  he  could  not  even  carry  on 
conversation  with  a  fellow  passenger  in  the 
machine  without  a  speaking-tube  fitted  to  mouth 
and  ears  so  as  to  cut  out  the  terrific  roar  of 
his  own  engine.  Now  the  range  of  his  voice 
has  been  so  extended  that  he  can  chat  with  fel- 
low aviators  miles  away.  This  remarkable 
achievement  and  many  others  in  the  field  of 
radio-communication  hinge  upon  a  delicate  elec- 
trical device  invented  by  Deforest  in  1906  and 
known  as  the  "audion."  For  years  this  in- 
strument was  used  by  radiotelegraphers  with- 

184 


TALKING  IN  THE  SKY  185 

out  a  real  appreciation  of  its  marvelous  possi- 
bilities, and,  as  a  matter  of  fact,  in  its  earlier 
crude  form  it  was  not  capable  of  performing  the 
wonders  it  has  achieved  since  it  was  taken  over 
and  developed  by  the  engineers  of  the  Bell  Tele- 
phone System. 

THE  AUDION 

Although  the  audion  is  familiar  to  all  ama- 
teur radio-operators,  we  shall  have  to  give  a 
brief  outline  of  its  construction  and  operation 
for  the  benefit  of  those  who  have  not  had  the 
opportunity  to  dabble  in  wireless  telegraphy. 

The  audion  is  a  small  glass  bulb  from  which 
the  air  is  exhausted  to  a  high  degree  of  vacuum. 
The  bulb  contains  three  elements.  One  is  a 
tiny  filament  which  is  heated  to  incandescence 
by  a  battery,  so  that  it  emits  negatively  charged 
electrons.  The  filament  is  at  one  side  of  the 
bulb  and  at  the  opposite  side  there  is  a  metal 
plate.  When  the  plate  and  the  filament  are 
connected  with  opposite  poles  of  a  battery,  there 
is  a  flow  of  current  between  them,  but  because 
only  negative  electrons  are  emitted  by  the 
filament,  the  current  will  flow  only  in  one  di- 
rection— that  is,  from  the  plate  to  the  filament 


186      INVENTIONS  OF  THE  GREAT  WAR 

If  the  audion  be  placed  in  the  circuit  of  an  alter- 
nating-current generator,  it  will  let  through 
only  the  current  running  in  one  direction. 
Thus  it  will  "rectify"  the  current  or  convert 
alternating  current  into  direct  current. 

But  the  most  important  part  of  the  audion,  the 
part  for  which  Deforest  is  responsible,  is  the 
third  element,  which  is  a  grid  or  flat  coil  of 
platinum  wire  placed  between  the  filament  and 
the  plate.  This  grid  furnishes  a  very  delicate 
control  of  the  strength  of  the  electric  current 
between  plate  and  filament.  The  slightest 
change  in  electric  power  in  the  grid  will  pro- 
duce large  changes  of  power  in  the  current 
flowing  through  the  audion.  This  makes  it 
possible  to  magnify  or  amplify  very  feeble  elec- 
tric waves,  and  the  extent  to  which  the  ampli- 
fying can  be  carried  is  virtually  limitless,  be- 
cause a  series  of  audions  can  be  used,  the  cur- 
rent passing  through  the  first  being  connected 
with  the  grid  of  the  next,  and  so  on. 

TALKING  FROM    NEW   YORK   TO   SAN   FRANCISCO 

There  is  a  limit  to  which  telephone  conversa- 
tions can  be  carried  on  over  a  wire,  unless  there 
is  some  way  of  adding  fresh  energy  along  the 


TALKING  IN  THE  SKY  187 

line.  For  years  all  sorts  of  experiments  were 
tried  with  mechanical  devices  which  would  re- 
ceive a  telephone  message  and  send  it  on  with 
a  fresh  relay  of  current.  But  these  devices  dis- 
torted the  message  so  that  it  was  unintelligible. 
The  range  of  wire  telephony  was  greatly  in- 
creased by  the  use  of  certain  coils  invented  by 
Pupin,  which  were  placed  in  the  line  at  inter- 
vals; but  still  there  was  a  limit  to  which  con- 
versation could  be  carried  on  by  wire  and  it 
looked  as  if  it  would  never  be  possible  to  tele- 
phone from  one  end  of  this  big  country  of  ours 
to  the  'other.  But  the  audion  supplied  a 
wonderfully  efficient  relay  and  one  day  we 
awoke  to  hear  San  Francisco  calling,  "  Hello, " 
to  New  York. 

Used  as  a  relay,  the  improved  audion  made  it 
possible  to  pick  up  very  faint  wireless-tele- 
graph messages  and  in  that  way  increased  the 
range  of  radio  outfits.  Messages  could  be  re- 
ceived from  great  distances  without  any  exten- 
sive or  elaborate  aerials,  and  the  audion  could 
be  used  at  the  sending-station  to  magnify  the 
signals  transmitted  and  send  them  forth  with 
far  greater  power. 

Having  improved  the  audion  and  used  it  sue- 


188      INVENTIONS  OF  THE  GREAT  WAR 

cessfully  for  long-distance  telephone  conversa- 
tion over  wires,  the  telephone  company  began 
to  experiment  with  wireless  telephony.  They 
believed  that  it  might  be  possible  to  use  radio- 
telephony  in  places  where  wires  could  not  be 
laid.  For  instance,  it  might  be  possible  to  talk 
across  the  Atlantic. 

But  before  we  go  farther,  just  a  word  of  ex- 
planation concerning  radiotelegraphy  and  radio- 
telephony  for  the  benefit  of  those  who  have 
not  even  an  elementary  knowledge  of  the 
subject. 

SIMPLE   EXPLANATION    OF   RADIOTELEGRAPHY 

Suppose  we  should  set  up  two  stakes  in  a  pond 
of  water,  at  some  distance  from  each  other,  and 
around  each  we  set  a  ring-shaped  cork  float.  If 
we  should  move  one  of  these  floats  up  and  down 
on  its  stake,  it  would  produce  ripples  in  the 
water  which  would  spread  out  in  all  directions 
and  finally  would  reach  the  opposite  stake  and 
cause  the  float  there  to  bob  up  and  down  in 
exactly  the  same  way  as  did  the  float  moved 
by  hand.  In  wireless  telegraphy  the  two  stakes 
are  represented  by  antennae  or  aerials  and  the 
cork  floats  are  electric  charges  which  are  sent 


TALKING  IN  THE  SKY  189 

oscillating  up  and  down  the  antennae.  The  os- 
cillations produced  at  one  aerial  will  set  up 
electro-magnetic  waves  which  will  spread  out 
in  all  directions  in  the  ether  until  they  reach  a 
receiving-aerial,  and  there  they  will  produce 
electric  oscillations  similar  to  the  ones  at  the 
transmitting-antenna. 

Telegraph  signals  are  sent  by  the  breaking 
up  of  the  oscillations  at  the  transmitting-station 
into  long  and  short  trains  of  oscillations  corre- 
sponding to  the  dots  and  dashes  of  ordinary 
wire  telegraphy.  In  other  words,  while  the 
sending-key  is  held  down  for  a  dash,  there  will 
be  a  long  series  of  oscillations  in  the  antenna, 
and  for  the  dot  a  short  series,  and  these  short 
and  long  trains  of  waves  will  spread  out  to  the 
receiving-aerial  where  they  will  reproduce  the 
same  series  of  oscillations.  But  only  a  small 
part  of  the  energy  will  act  on  the  receiving- 
aerial  because  the  waves  like  those  on  the  pond 
spread  in  all  directions  and  grow  rapidly 
weaker.  Hence  the  advantage  of  an  extremely 
delicate  instrument  like  the  audion  to  amplify 
the  signals  received. 

The  oscillations  used  in  wireless  telegraphy 
these  days  are  very  rapid,  usually  entirely  too 


190      INVENTIONS  OF  THE  GREAT  WAR 

rapid,  to  affect  an  ordinary  telephone  receiver, 
and  if  they  did  they  would  produce  a  note  of 
such  high  pitch  that  it  could  not  be  heard.  So 
it  is  customary  to  interrupt  the  oscillations, 
breaking  them  up  into  short  trains  of  waves, 
and  these  successive  trains  produce  a  note  of 
low  enough  pitch  to  be  heard  in  the  telephone 
receiver.  Of  course  the  interruptions  are  of 
such  high  frequency  that  in  the  sending  of  a  dot- 
and-dash  message  each  dot  is  made  up  of  a  great 
many  of  the  short  trains  of  waves. 

Now  in  radiotelephony  it  is  not  necessary  to 
break  up  the  oscillations,  but  they  are  allowed  to 
run  continuously  at  very  high  speed  and  act  as 
carriers  for  other  waves  produced  by  speaking 
into  the  transmitter;  that  is,  a  single  speech- 
wave  would  be  made  up  of  a  large  number 
of  smaller  waves.  To  make  wireless  tele- 
phony a  success  it  was  necessary  to  find  some 
way  of  making  perfectly  uniform  carrier-waves, 
and  then  of  loading  on  them  waves  of  speech. 
Of  course,  the  latter  are  not  sound-waves,  be- 
cause they  are  not  waves  of  air,  but  they  are 
electro-magnetic  waves  corresponding  exactly 
to  the  sound-waves  of  air  and  at  the  receiving- 
end  they  affect  the  telephone  receiver  in  the 


TALKING  IN  THE  SKY  191 

same  way  that  it  is  affected  by  the  electric 
waves  which  are  sent  over  telephone  wires.  The 
telephone  engineers  found  that  the  audion 
could  be  used  to  regulate  the  carrier-waves  and 
also  to  superpose  the  speech-waves  upon  them, 
and -at  the  receiving- station  the  audion  was  used 
to  pick  up  these  waves,  no  matter  how  feeble 
they  might  be,  'and  amplify  them  so  that  they 
could  be  heard  in  a  telephone  receiver. 

TALKING   WITHOUT   WIRES 

Attempts  at  long-distance  talking  without 
wires  were  made  from  Montauk  Point,  on  the 
tip  of  Long  Island,  to  Wilmington,  Delaware, 
and  they  were  successful.  This  was  in  1915. 
The  apparatus  was  still  further  improved  and 
then  the  experiment  was  tried  of  talking  from 
the  big  Arlington  station  near  Washington  to 
Darien,  on  the  Isthmus  of  Panama.  This  was 
a  distance  of  twenty-one  hundred  miles,  and 
speech  was  actually  transmitted  through  -space 
over  that  great  distance.  That  having  proved 
successful,  the  next  attempt  was  to  talk  from 
Arlington  to  Mare  Island  and  San  Diego,  on  the 
Pacific  Coast,  a  distance  of  over  twenty-five 
hundred  miles.  This  proved  a  success,  too,  and 


192      INVENTIONS  OF  THE  GREAT  WAR 

it  was  found  possible  even  to  talk  as  far  as 
Honolulu. 

The  engineers  now  felt  confident  that  they 
could  talk  across  the  Atlantic  to  Europe,  and 
so  in  October  of  1915  arrangements  were  made 
to  conduct  experiments  between  Arlington  and 
the  Eiffel  Tower  in  Paris.  Although  the  war 
was  at  its  height,  and  the  French  were  strain- 
ing every  effort  to  hold  back  the  Germans  at 
that  time,  and  although  there  were  constant  de- 
mands for  the  use  of  radiatelegraphy,  the 
French  showed  such  an  appreciation  of  science 
that  they  were  willing  to  lend  their  aid  to  these 
experiments.  The  Eiffel  Tower  could  be  used 
only  for  short  periods  of  time,  and  there  was 
much  interference  from  other  high-powered 
stations.  Nevertheless,  the  experiment  proved 
perfectly  successful,  and  conversation  was  car- 
ried on  between  our  capital  and  that  of  France, 
a  distance  of  thirty-six  hundred  miles.  At  the 
same  time,  an  operator  in  Honolulu,  forty-five 
hundred  miles  away,  heard  the  messages,  and 
so  the  voice  at  Arlington  carried  virtually  one 
third  of  the  way  around  the  globe.  After  that 
achievement,  there  was  a  lull  in  the  wireless- 
telephone  experiments  because  of  the  war. 


(C)  G.  V.  Buck 

Radio  Head-gear  of  an  Airman 


(C)  G.  V.  Buck 

Carrying  on  Conversation  by  Radio  with  an  Aviator 
Miles  Away 


TALKING  IN  THE  SKY  193 

But  there  soon  came  an  opportunity  to  make 
very  practical  use  of  all  the  experimental  work. 
As  soon  as  there  seemed  to  be  a  possibility  that 
we  might  be  drawn  into  the  war,  the  Secretary 
of  the  Navy  asked  for  the  design  of  apparatus 
that  would  make  it  possible  for  ships  to  converse 
with  one  another  and  with  shore  stations.  Of 
course  all  vessels  are  equipped  with  wireless- 
telegraph  apparatus,  but  there  is  a  decided  ad- 
vantage in  having  the  captain  of  one  ship  talk 
directly  with  the  captain  of  another  ship,  or 
take  his  orders  from  headquarters,  with  an 
ordinary  telephone  receiver  and  transmitter. 
A  special  equipment  was  designed  for  battle- 
ships and  on  test  it  was  found  that  ships  could 
easily  converse  with  one  another  over  a  distance 
of  thirty-five  miles  and  to  shore  stations  from 
a  distance  of  a  hundred  and  seventy-five  miles. 
The  'apparatus  was  so  improved  that  nine  con- 
versations could  be  carried  on  at  the  same  time 
without  any  interference  of  one  by  the  others. 

When  it  became  certain  that  we  should  have 
to  enter  the  war,  there  came  a  call  for  radio- 
telephone apparatus  for  submarine-chasers,  and 
work  was  started  on  small,  compact  outfits  for 
these  little  vessels. 


194      INVENTIONS  OF  THE  GREAT  WAR 

RADIOTELEPHONES   FOB   AIRPLANES 

Then  there  was  a  demand  for  radiotelephone 
apparatus  to  be  used  on  airplanes.  This  was  a 
much  more  complicated  matter  and  called  for  a 
great  deal  of  study.  The  way  in  which  problem 
after  problem  arose  and  was  solved  makes  an 
exceedingly  interesting  narrative.  It  seemed 
almost  absurd  to  think  that  a  delicate  radio- 
telegraph apparatus  could  be  made  to  work  in 
the  terrific  noise  and  jarring  of  an  airplane. 
The  first  task  was  to  make  the  apparatus  noise- 
proof. A  special  sound-proof  room  was  con- 
structed in  which  a  noise  was  produced  exactly 
imitating  that  of  the  engine  exhaust  of  an  air- 
plane engine.  In  this  room,  various  helmets 
were  tried  in  order  to  see  whether  they  would 
be  proof  against  the  noise,  and  finally  a  very 
suitable  helmet  was  designed,  in  which  the  tele- 
phone receiver  and  transmitter  were  installed. 

By  summer-time  the  work  had  proceeded  so 
far  that  an  airplane  equipped  with  transmitting- 
apparatus  could  send  spoken  messages  to  an 
operator  on  the  ground  from  a  distance  of  two 
miles.  The  antenna  of  the  airplane  consisted 
of  a  wire  with  a  weight  on  the  lower  end,  which 


TALKING  IN  THE  SKY  195 

hung  down  about  one  hundred  yards  from  the 
body  of  the  machine.  But  a  trailing  antenna 
was  a  nuisance  in  airplane  manoeuvers,  and  it 
was  also  found  that  the  helmet  which  was  so 
satisfactory  in  the  laboratory  was  not  just  the 
thing  for  actual  service  in  an  airplane.  It  had 
to  fit  very  tightly  around  the  ears  and  the 
mouth,  and  as  the  airplane  went  to  high  alti- 
tudes where  the  air-pressure  was  much  lower 
than  at  the  ground  level,  painful  pressures  were 
produced  in  the  ears  which  were  most  annoy- 
ing. Aside  from  that,  -in  actual  warfare  air- 
planes have  to  operate  at  extreme  heights, 
where  the  air  is  so  rare  that  oxygen  must  be 
supplied  to  the  aviators,  and  it  was  difficult  to 
provide  this  supply  of  oxygen  with  the  radio 
helmet  tightly  strapped  to  the  head  of  the  op- 
erator. But  after  considerable  experiment,  this 
difficulty  was  overcome  and  also  that  of  the 
varying  pressures  on  the  ears. 

Another  great  difficulty  was  to  obtain  a  steady 
supply  -of  power  on  the  airplane  to  operate  the 
transmitting-apparatus.  It  has  been  the  prac- 
tice to  supply  current  on  airplanes  for  wireless- 
telegraph  apparatus  by  means  of  a  small  elec- 
tric generator  which  is  revolved  by  a  little  pro- 


196      INVENTIONS  OF  THE  GREAT  WAR 

peller.  The  propeller  in  turn  is  revolved  by 
the  rush  of  air  as  it  is  carried  along  by  the  plane. 
But  the  speed  of  the  airplane  varies  consider- 
ably. At  times,  it  may  be  traveling  at  only 
forty  miles  per  hour,  and  at  other  times  as  high 
as  one  hundred  and  sixty  miles  per  hour,  so 
that  the  little  generator  is  subjected  to  great 
variations  of  speed  and  consequent  variations 
of  voltage.  This  made  it  impossible  to  produce 
the  steady  oscillations  -that  are  required  in  wire- 
less telephony.  After  considerable  experiment, 
a  generator  was  produced  with  two  windings, 
one  of  which  operated  through  a  vacuum  tube, 
somewhat  like  an  audion,  and  to  resist  the  in- 
crease of  voltage  produced  by  the  other  winding. 
Then  another  trouble  developed.  The  sparks 
produced  by  the  magneto  in  the  airplane  motor 
set  up  electro-magnetic  waves  which  seriously 
affected  the  receiving-instrument.  There  was 
no  way  of  getting  rid  of  the  magneto,  but  the 
wires  leading  from  it  to  the  engine  were  in- 
cased in  metal  tubes  which  were  grounded  at 
frequent  intervals,  and  in  that  way  the  trouble 
was  overcome  to  a  large  extent.  The  magnetos 
themselves  were  also  incased  in  such  a  way  that 


TALKING  IN  THE  SKY  197 

electro-magnetic  waves  would  not  be  radiated 
from  them. 

Instead  of  using  trailing  wires  which  were 
liable  to  become  entangled  in  the  propeller,  the 
antenna  was  extended  from  the  upper  plane  to 
the  tail  of  the  machine,  and  later  it  was  found 
that  by  using  two  short  trailing  antennae  one 
from  each  tip  of  the  wings,  the  very  best  results 
could  be  obtained.  Still  another  development 
was  to  embed  the  antenna  wires  in  the  wings 
of  the  plane. 

It  was  considered  necessary,  if  the  apparatus 
was  to  be  practicable,  to  be  able  to  use  it  over 
a  distance  of  two  thousand  yards,  but  in  experi- 
ments conducted  in  October,  1917,  a  couple  of 
airplanes  were  able  to  talk  to  each  other  when 
twenty-three  miles  apart,  and  conversations 
were  carried  on  with  the  ground  from  a  distance 
of  forty-five  miles.  The  conditions  under  which 
these  distances  were  attained  were  unusual,  and 
a  distance  of  three  miles  was  accepted  as  a 
standard  for  communication  between  airplanes. 
The  apparatus  weighed  only  fifty-eight  pounds 
and  it  was  connected  with  both  the  pilot  and  the 
observer  so  that  they  could  carry  on  conversa- 


198      INVENTIONS  OF  THE  GREAT  WAR 

tions  with  each  other  and  could  both  hear 
the  conversation  with  other  airplanes  or  the 
ground.  As  a  matter  of  fact,  airplanes  with 
standard  apparatus  are  able  to  talk  clearly  to  a 
distance  of  five  miles  and  even  to  a  distance  of 
ten  miles  when  conditions  are  favorable,  and 
they  can  receive  messages  from  the  ground  over 
almost  any  distance. 

A  similar  apparatus  was  constructed  for  sub- 
marine-chasers with  a  standard  range  of  con- 
versation of  over  five  miles.  Apparatus  was 
manufactured  in  large  quantities  in  this  country 
and  all  our  submarine-chasers  were  equipped 
with  it,  as  well  as  a  great  many  of  our  airplanes 
and  seaplanes,  and  we  furnished  radio-appa- 
ratus sets  to  our  allies  which  proved  of  im- 
mense value  in  the  war.  This  was  particularly 
so  in  the  case  of  submarine  detection,  when  it 
was  possible  for  a  seaplane  or  a  balloon  to  re- 
port its  findings  at  once  to  submarine-chasers 
and  destroyers,  and  to  guide  them  in  pursuit  -of 
submarines. 

The  improved  audion  holds  out  a  wonder- 
ful future  for  radiotelephony.  For  receiving, 
at  least,  no  elaborate  aerial  will  be  needed,  and 
with  a  small  loop  of  wire,  an  audion  or  two, 


TALKING  IN  THE  SKY  199 

and  simple  tuning-apparatus  any  one  can  hear 
the  radio  gossip  of  the  whole  world. 

TELEGRAPHING   TWELVE   HTJNDKED   WOBDS  PEB 
MINUTE 

Some  remarkable  advances  were  made  in 
telegraphy  also.  During  the  war  and  since, 
messages  have  been  sent  direct  from  Washing- 
ton to  all  parts  of  the  world.  In  the  telegraph 
room  operators  are  connected  by  wire  with  the 
different  radio  stations  along  the  coast -and  they 
can  control  the  radio  transmitters,  sending  their 
messages  without  any  repeating  at  the  radio 
stations.  Long  messages  are  copied  off  on  a 
machine  something  like  a  type-writer,  which, 
however,  does  not  make  type  impressions,  but 
cuts  perforations  in  a  long  sheet  of  paper.  The 
paper  is  then  run  through  a  transmitter  at  a 
high  speed  and  the  message  is  sent  out  at  a  rate 
of  as  much  as  twelve  hundred  words  a  minute. 
At  the  receiving-station,  the  message  is  received 
photographically  on  a  strip  of  paper.  The  re- 
ceiving-instrument has  a  fine  quartz  thread  in 
it,  which  carries  a  tiny  mirror.  A  beam  of  light 
is  reflected  from  the  mirror  upon  the  strip  of 
sensitized  paper.  The  radio  waves  twist  the 


200      INVENTIONS  OF  THE  GREAT  WAR 

quartz  thread  ever  so  slightly,  which  makes  the 
beam  of  light  play  back  and  forth,  but  of  course 
the  motion  is  greatly  magnified.  In  this  way 
a  perfect  record  is  made  of  the  message  in  dots 
and  dashes,  which  are  translated  into  the  corre- 
sponding letters  of  the  alphabet. 

DETECTING  BADIO   SPIES 

There  is  another  radio  invention  which  we 
contributed  during  the  war,  that  proved  of  ut- 
most service  in  thwarting  German  spies  and 
which  is  going  to  prove  equally  valuable  in  time 
of  pe'ace.  Although  a  war  invention,  its  peace- 
time service  will  be  to  save  lives.  It  is  a  very 
simple  matter  to  rig  up  a  wireless-telegraph 
system  that  will  send  messages  to  a  considerable 
distance,  and  simpler  still  to  rig  up  a  receiving- 
set.  European  governments  have  always  dis- 
couraged amateur  radiotelegraphy,  but  in  this 
country  restrictions  used  to  be  so  slight  that 
almost  any  one  could  set  up  and  use  a  radio 
set,  both  for  receiving  and  for  transmitting. 
When  we  entered  the  war  we  were  glad  that 
amateurs  had  been  encouraged  to  play  with 
wireless,  because  we  had  hundreds  of  good  radio 


TALKING  IN  THE  SKY  201 

operators  ready  to  work  the  sets  which  the  army 
and  the  navy  needed. 

But  this  was  a  disadvantage,  too.  Many 
operators  were  either  Germans  or  pro-Germans 
and  were  only  too  willing  to  use  their  radio  ex- 
perience in  the  interest  of  our  enemies.  It  was 
a  simple  matter  to  obtain  the  necessary  appa- 
ratus, because  there  was  plenty  of  it  to  be  had 
everywhere.  They  could  send  orders  to  fellow 
workers  and  receive  messages  from  them,  or 
they  could  listen  to  dispatches  sent  out  by  the 
government  and  glean  information  of  great  mili- 
tary and  naval  importance.  The  apparatus 
could  easily  be  concealed:  a  wire  hung  inside 
a  chimney,  a  water-pipe,  even  a  brass  bedstead 
could  be  used  for  the  receiving-aerial.  It  was 
highly  important  that  these  concealed  stations 
be  located,  but  how  were  they  to  be  discovered? 

THE   WIRELESS  COMPASS 

This  problem  was  solved  very  nicely.  The 
audion  had  made  it  possible  to  receive  radio 
signals  on  a  very  small  aerial.  In  place  of  the 
ordinary  stationary  aerial  a  frame  five  feet 
square  was  set  up  so  that  it  could  be  turned 


202      INVENTIONS  OF  THE  GREAT  WAR 

to  any  point  of  the  compass.  A  few  turns  of 
copper-bronze  wire  were  wound  round  it.  This 
was  called  the  "wireless  compass/'  It  was  set 
up  on  the  roof  of  the  radio  station  and  concealed 
within  a  cupola.  The  shaft  on  which  it  was 
mounted  extended  down  into  the  operating- 
room  and  carried  a  wheel  by  which  it  could  be 
turned.  On  the  shaft  was  a  circular  band  of 
aluminum  engraved  with  the  360  degrees  of  the 
circle,  and  a  couple  of  fixed  pointers  indicated 
true  north  and  south.  Now  when  a  signal  was 
received  by  the  aerial,  if  it  struck  the  frame 
edgewise  the  radio  waves  would  reach  one  side 
before  they  would  the  other.  Taking  a  single 
wave,  as  shown  by  the  drawing,  Fig.  11,  we 
see  that  while  the  crest  of  the  wave  is  sweep- 
ing over  one  side  of  the  frame,  the  trough  of  the 
wave  is  passing  the  other  side.  Two  currents 
are  set  up  in  the  radio  compass,  one  in  the 
wires  at  the  near  side  of  the  compass,  and  an- 
other in  the  wires  at  the  far  side  of  the  com- 
pass. As  these  currents  are  of  the  same  direc- 
tion, they  oppose  each  other  and  tend  to  kill 
each  other  off,  but  one  of  the  currents  is 
stronger  than  the  other  because  the  crest  of  the 
wave  is  sweeping  over  that  side,  while  the 


Courtesy   of  th»  "Scientific  American" 

FIG.  11.     The  radio  compass  turned  parallel  to  an  oncoming 
electro-magnetic  wave 


203 


204      INVENTIONS  OF  THE  GREAT  WAK 

trough  of  the  wave  is  passing  over  the  other. 
The  length  of  the  wave  may  be  anything,  but 
always  one  side  will  be  stronger  than  the  other, 
and  a  current  equal  in  strength  to  the  difference 
between  the  two  currents  goes  down  into  the 
operating-room  and  affects  the  receiver.  Now 
when  the  compass  is  set  at  right  angles  to  the 
oncoming  wave,  both  sides  are  affected  simul- 
taneously and  with  the  same  strength,  so  that 
they  kill  each  other  off  completely,  and  no 
current  goes  down  to  the  receiver.  Thus  the 
strength  of  the  signal  received  can  be  varied 
from  a  maximum,  when  the  compass  is  parallel 
to  the  oncoming  waves,  to  zero,  when  it  is  at 
right  angles  to  them. 

To  find  out  where  a  sending-station  is,  the 
compass  is  turned  until  the  loudest  sound  is 
heard  in  the  receiver  and  then  the  campass 
dial  shows  from  what  direction  the  signals  are 
coming.  At  the  same  time,  another  line  on  the 
signals  will  be  found  by  a  second  station  with 
another  compass.  These  directions  are  traced 
on  a  map;  and  where  they  meet,  the  sending- 
station  must  be  located. 

With  this  apparatus  it  was  possible  to  locate 
the  direction  of  the  station  within  a  degree. 


TALKING  IN  THE  SKY  205 

After  the  station  had  been  located  as  closely 
as  possible  in  this  way,  a  motor-truck  was  sent 
out  in  which  there  was  a  concealed  radio  com- 
pass. The  truck  would  patrol  the  region 
located  by  the  fixed  compasses,  and  with  it  the 
position  of  the  concealed  station  could  be  de- 
termined with  perfect  accuracy.  The  building 
would  be  raided  and  its  occupants  jailed  and  the 
radio  equipment  confiscated. 

Even  receiving-sets  were  discovered  with  the 
portable  compass,  but  to  find  them  was  a  far 
more  difficult  task.  For  the  receiving  of  mes- 
sages from  distant  points  without  a  conspicuous 
aerial  an  audion  would  have  to  be  used  and  this 
would  set  up  feeble  oscillations  which  could  be 
picked  up  under  favorable  conditions  by  the 
portable  compass. 

PILOTING   SHIPS   INTO   POET 

And  now  for  the  peace-time  application  of  all 
this.  If  the  compass  could  be  used  to  find  those 
who  tried  to  hide,  why  could  it  not  also  be  used 
to  find  those  who  wished  to  be  found? 

Every  now  and  then  a  ship  runs  upon  the 
rocks  because  it  has  lost  its  bearings  in  the  fog. 
But  there  will  be  no  excuse  for  such  accidents 


206      INVENTIONS  OF  THE  GREAT  WAR 

now.  A  number  of  radio-compass  stations  have 
been  located  around  the  entrance  and  approach 
to  New  York  Harbor.  Similar  stations  have 
been,  or  soon  will  be,  established  at  other  ports. 
As  soon  as  a  ship  arrives  within  fifty  or  a 
hundred  miles  of  port  she  is  required  to  call  for 
her  bearings.  The  operator  of  the  control  sta- 
tion instructs  the  ship  to  send  her  call  letters 
for  thirty  seconds,  and  at  the  same  time  notifies 
each  compass  station  to  get  a  bearing  on  the 
ship.  This  each  does,  reporting  back  to  the  con- 
trol station.  The  bearings  are  plotted  on  a 
chart  and  inside  of  two  minutes  from  the  time 
the  ship  gives  her  call  letters,  her  bearing  is 
flashed  to  her  by  radio  from  the  control  station. 
The  chart  on  which  the  plotting  is  done  is 
covered  with  a  sheet  of  glass.  Holes  are 
pierced  through  the  glass  at  the  location  of  each 
compass  station.  See  Fig.  12.  On  the  chart, 
around  each  station,  there  is  a  dial  marked  off 
in  the  360  degrees  of  the  circle.  A  thread 
passes  through  the  chart  and  the  hole  in  the 
glass  at  each  station.  These  threads  are  at- 
tached to  weights  under  the  chart.  When  a 
compass  station  reports  a  bearing,  the  thread 
of  that  station  is  pulled  out  and  extended  across 


207 


208      INTENTIONS  OF  THE  GREAT  WAR 

the  corresponding  degree  on  the  dial.  The 
same  is  done  as  each  station  reports  and  where 
the  threads  cross,  the  ship  must  be  located. 

Not  only  can  the  direction-finder  be  used  to 
pilot  a  ship  into  a  harbor,  but  it  will  also  serve 
to  prevent  collisions  at  sea,  because  a  ship 
equipped  with  a  radio  compass  can  tell  whether 
another  ship  is  coming  directly  toward  her. 

And  so  as  one  of  the  happy  outcomes  of  the 
dreadful  war,  we  have  an  apparatus  that  will 
rob  sea-fogs  of  their  terrors  to  navigation. 


CHAPTER  XI 

WARRIORS  OF  THE  PAINT-BRUSH 

WHEN  the  great  European  war  broke  out, 
it  was  very  evident  that  the  Entente 
Allies  would  have  to  exercise  every  resource 
to  beat  the  foe  which  had  been  preparing  for 
years  to  conquer  the  world.  But  who  ever 
imagined  that  geologists  would  be  called  in  to 
choose  the  best  places  for  boring  mines  under 
the  enemy:  that  meteorologists  would  be  sum- 
moned to  forecast  the  weather  and  determine 
the  best  time  to  launch  an  offensive ;  that  psy- 
cologists  would  be  employed  to  pick  out  the  men 
with  the  best  nerves  to  man  the  machine-guns 
and  pilot  the  battle-planes?  Certainly  no  one 
guessed  that  artists  and  the  makers  of  stage 
scenery  would  play  an  important  part  in  the 
conflict. 

But  the  airplane  filled  the  sky  with  eyes  that 
at  first  made  it  impossible  for  an  army  to  con- 
ceal its  plans  from  the  enemy.  And  then  there 

209 


210      INVENTIONS  OF  THE  GREAT  WAR 

were  eyes  that  swam  in  the  sea — cruel  eyes  that 
belonged  to  deadly  submarine  monsters,  eyes 
that  could  see  without  being  seen,  eyes  that 
could  pop  up  out  of  the  water  at  unexpected 
moments,  eyes  that  directed  deadly  missies  at 
inoffensive  merchantmen.  They  were  cowardly 
eyes,  too,  which  gave  the  ship  no  opportunity 
to  strike  back  at  the  unseen  enemy.  A  vessel's 
only  safety  lay  in  the  chance  that  out  in  the 
broad  reaches  of  the  ocean  it  might  pass  beyond 
the  range  of  those  lurking  eyes.  It  was  a  game 
of  hide-and-seek  in  which  the  pursuer  and  not 
the  pursued  was  hidden.  Something  had  to  be 
done  to  conceal  the  pursued  as  well,  but  in  the 
open  sea  there  was  nothing  to  hide  behind. 

HIDING   IN   PLAIN   SIGHT 

There  is  such  a  thing  as  hiding  in  plain  sight. 
You  can  look  right  at  a  tree-toad  without  see- 
ing him,  because  his  colors  blend  perfectly  with 
the  tree  to  which  he  is  clinging.  You  can  watch 
a  green  leaf  curl  up  and  shrivel  without  realiz- 
ing that  the  curled  edge  is  really  a  caterpillar, 
cunningly  veined  and  colored  to  look  just  like 
a  dying  leaf;  and  out  in  the  woods  a  speckled 
bird  or  striped  animal  will  escape  observation 


WARRIORS  OF  THE  PAINT-BRUSH      211 

just  because  it  matches  the  spotted  light  that 
comes  through  the  underbrush.  Nature  is 
constantly  protecting  its  helpless  animals 
with  colored  coats  that  blend  with  the  sur- 
roundings. 

Long  ago  clumsy  attempts  at  concealment 
were  made  when  war-vessels  were  given  a  coat 
of  dark-gray  paint  which  was  supposed  to  make 
them  invisible  at  a  distance.  Actually  the 
paint  made  them  more  conspicuous;  but,  then, 
concealment  did  not  count  for  very  much  be- 
fore the  present  war. 

It  was  the  eyes  of  the  submarines  that 
brought  a  hurry  call  for  the  artists,  and  up  to 
them  was  put  the  problem  of  hiding  ships  in 
plain  sight.  A  new  name  was  coined  for  these 
warriors  of  the  paint-brush:  camoufleurs  they 
were  called,  and  their  work  was  known  as 
camouflage. 

MATCHING    THE   SKY 

Of  course,  no  paint  will  make  a  ship  abso- 
lutely invisible  at  a  short  distance,  but  a  large 
vessel  may  be  made  to  disappear  completely 
from  view  at  a  distance  of  six  or  seven  miles 
if  it  is  properly  painted. 


212      INVENTIONS  OF  THE  GREAT  WAR 

To  be  invisible,  a  ship  must  reflect  as  much 
light  and  the  same  shade  of  light  as  do  its  sur- 
roundings. If  it  is  seen  against  the  background 
of  the  sea,  it  must  be  of  a  bluish  or  a  greenish 
tint,  but  a  submarine  lies  so  low  in  the  water 
that  any  object  seen  at  a  distance  is  silhouetted 
against  the  sky,  and  so  the  ship  must  have  a 
coat  of  paint  that  will  reflect  the  same  colors 
as  does  the  sky.  Now,  the  sky  may  be  of  almost 
any  color  of  the  rainbow,  depending  upon  the 
position  of  the  sun  and  the  amount  of  vapor  or 
dust  in  the  air.  Fortunately  in  the  North 
Sea  and  the  waters  about  the  British  Isles, 
where  most  of  the  submarine  attacks  took  place, 
the  weather  is  hazy  most  of  the  time,  and  the 
ship  had  to  be  painted  of  such  a  color  that  it 
would  reflect  the  same  light  as  that  reflected  by 
a  hazy  sky.  With  a  background  of  haze  and 
more  or  less  haze  between  the  ship  and  the 
periscope  of  the  U-boat,  it  was  not  a  very  diffi- 
cult matter  to  paint  a  ship  so  that  it  would  be 
invisible  six  or  seven  miles  away.  One  shade  of 
gray  was  used  to  conceal  a  ship  in  the  North 
Sea  and  an  entirely  different  shade  was  used 
for  the  brighter  skies  of  the  Mediterranean. 

In  this  way,  the  artists  made  it  possible  for 


WABRIORS  OF  THE  PAINT-BRUSH      213 

ships  to  sail  in  safety  much  nearer  the  pursuer 
who  was  trying  to  find  them,  and  by  just  so  much 
they  reduced  his  powers  of  destruction.  But 
still  the  odds  were  too  heavy  against  the  mer- 
chantman. Something  must  be  done  for  him 
when  he  found  himself  within  the  seven-mile 
danger-zone.  Here  again  the  artists  came  to 
the  rescue. 

Before  merchant  ships  were  armed,  a  sub- 
marine would  not  waste  a  torpedo  on  them,  but 
would  pound  them  into  submission  with  shell. 
Even  after  ships  were  provided  with  guns,  sub- 
marines mounted  heavier  guns  and  unless  a 
ship  was  speedy  enough  to  show  a  clean  pair 
of  heels,  the  pursuing  U-boat  would  stand  off 
out  of  range  of  the  ship's  guns  and  pour  a 
deadly  fire  into  it.  But  the  ships,  too,  mounted 
larger  guns  and  the  submarines  had  to  fall  back 
upon  their  torpedoes. 

GETTING   THE    RANGE   FOE   THE    TORPEDO 

In  order  to  fire  its  torpedo  with  any  certainty, 
the  U-boat  had  to  get  within  a  thousand  yards 
of  its  victim.  A  torpedo  travels  at  from 
thirty  to  forty  miles  per  hour.  It  takes  time 
for  it  to  reach  its  target  and  a  target  which 


214      INVENTIONS  OF  THE  GREAT  WAR 

is  moving  at,  say,  fifteen  knots,  will  travel 
five  hundred  yards  while  a  thirty-knot  tor- 
pedo is  making  one  hundred  yards.  And  so 
before  the  U-boat  commander  could  discharge 
his  torpedo,  he  had  to  know  how  fast  the 
ship  was  traveling  and  how  far  away  it  was 
from  him.  He  could  not  come  to  the  surface 
and  make  deliberate  observations,  but  had  to 
stay  under  cover,  not  daring  even  to  keep  his 
eye  out  of  water,  for  fear  that  the  long  wake 
of  foam  trailing  behind  -the  periscope  would 
give  him  away.  All  he  could  do,  then,  was 
to  throw  his  periscope  up  for  a  momentary 
glimpse  and  make  his  calculations  very  quickly ; 
then  he  could  move  to  the  position  he  figured 
that  he  should  occupy  and  shoot  up  his  peri- 
scope for  another  glimpse  to  check  up  his  calcu- 
lations. On  the  glass  of  this  periscope,  there 
were  a  number  of  graduations  running  verti- 
cally and  horizontally.  If  he  knew  his  victim 
and  happened  to  know  the  height  of  its  smoke- 
stacks or  the  length  of  the  boat,  he  noted  how 
many  graduations  they  covered,  and  then  by  a 
set  formula  he  could  tell  how  far  he  was  from 
the  boat.  At  the  same  time  he  had  to  work  out 
its  rate  of  travel  and  note  carefully  the  course 


WARRIORS  OF  THE  PAINT-BRUSH     215 

it  was  holding  before  he  could  figure  where 
his  torpedo  must  be  aimed. 

There  was  always  more  or  less  uncertainty 
about  such  observations,  because  they  had  to  be 
taken  hastily,  and  the  camoufleurs  were  not  slow 
to  take  advantage  of  this  weakness.  They  in- 
creased the  enemy's  confusion  by  painting  high 
bow-waves  which  made  the  ship  look  as  if  it  were 
traveling  at  high  speed.  They  painted  the 
bow  to  look  like  the  stern,  and  the  stern  to  look 
like  the  bow,  and  the  stacks  were  painted  so  that 
they  appeared  to  slant  in  the  opposite  direc- 
tion, so  that  it  would  look  as  if  the  vessel  were 
headed  the  other  way.  U-boats  came  to  have  a 
very  wholesome  respect  for  destroyers  and 
would  seldom  attack  a  ship  if  one  of  these 
fast  fighting-craft  was  about,  and  so  destroyers 
were  painted  on  the  sides  of  ships  as  scare- 
crows to  frighten  off  the  enemy. 

MAKING   STRAIGHT   LINES   LOOK    CEOOKED 

We  say  that  "seeing  is  believing,"  but  it  is 
not  very  hard  to  deceive  the  eye.  The  lines  in 
Fig.  13  look  absolutely  parallel,  and  they  are; 
but  cross-hatch  the  spaces  between  them,  with 
the  hatching  reversed  in  alternate  spaces,  as  in 


FIG.  13.     Parallel  lines  that  look  straight 


FIG.  14.    Parallel  lines  that  do  not  look  straight 


**       n    n  r» 

F  yipl 

usa»       twU  u    \ 


Lirt  Lir 


Courtesy  of  the  Submarine  Defense  Association 
FIG.  15.    Letters  that   look  all  higgledy-piggledy,  but  are 
really  straight 


216 


WARRIORS  OF  THE  PAINT-BRUSH     217 

Fig.  14,  and  they  no  longer  look  straight. 
Take  the  letters  on  the  left,  Fig.  15.  They 
look  all  higgledy-piggledy,  but  they  are  really 
straight  and  parallel,  as  one  can  prove  by  laying 
a  straight-edge  against  them,  or  by  drawing 
a  straight  line  through  each  letter,  as  shown  at 
the  right,  Fig.  16.  Such  illusions  were  used  on 
ships.  Stripes  were  painted  on  the  hull  that 
tapered  slightly,  from  bow  to  stern,  so  that  the 
vessel  appeared  to  be  headed  off  at  an  angle, 
when  it  was  really  broadside  to  the  watcher  at 
the  other  end  of  the  periscope. 

There  are  color  illusions,  too,  that  were  tried. 
If  you  draw  a  red  chalk -mark  and  a  blue  one  on 
a  perfectly  clean  blackboard,  the  red  line  will 
seem  to  stand  out  and  the  blue  one  to  sink  into 
the  black  surface  of  the  board,  because  your  eye 
has  to  focus  differently  for  the  two  colors,  and 
a  very  dazzling  effect  can  be  had  with  alternat- 
ing squares  of  blue  and  red.  Other  colors  give 
even  more  dazzling  effects,  and  some  of  them, 
when  viewed  at  a  distance,  will  blend  into  the 
very  shade  of  gray  that  will  make  a  boat  invisi- 
ble 'at  six  miles.  When  U-boat  commanders 
took  observations  on  a  ship  painted  with  a 
i 'dazzle"  camouflage,  they  saw  a  shimmering 


218      INVENTIONS  OF  THE  GREAT  WAR 

image  which  it  was  hard  for  them  to  measure  on 
the  fine  graduations  of  their  periscopes.  Some 
ships  were  painted  with  heavy  blotches  of  black 
and  white,  and  the  enemy  making  a  hasty  ob- 
servation would  be  apt  to  focus  his  attention 
on  the  dark  masses  and  overlook  the  white  parts. 
So  he  was  likely  to  make  a  mistake  in  estimating 
the  height  of  the  smoke-stack  or  in  measuring 
the  apparent  length  of  a  vessel. 

A   JOKE   ON   THE   PHOTOGBAPHEE 

Early  in  the  submarine  campaign  one  of  our 
boats  was  given  a  coat  of  camouflage,  and  when 
the  vessel  sailed  from  its  pier  in  the  North 
Eiver,  New  York,  the  owners  sent  a  photog- 
rapher two  or  three  piers  down  the  river  to 
photograph  the  ship  as  she  went  by.  He  took 
the  picture,  but  when  the  negative  was  de- 
veloped, much  to  his  astonishment  he  found 
that  the  boat  was  not  all  on  the  plate.  In  the 
finder  of  his  camera,  he  had  mistaken  a  heavy 
band  of  black  paint  for  the  stern  of  the  ship, 
quite  overlooking  the  real  stern,  which  was 
painted  a  grayish  white.  The  artist  had  fooled 
the  photographer  and  at  a  distance  of  not  nrore 
than  two  or  thre£  hundred  yards! 


WARRIORS  OF  THE  PAINT-BRUSH     219 

SEEING   BEYOND    THE    HOBIZON 

The  periscope  of  a  submarine  that  is  running 
awash  can  be  raised  about  fifteen  feet  above 
the  water,  which  means  that  the  horizon  as 
viewed  from  that  elevation  is  about  six  miles 
away,  and  if  you  draw  a  circle  with  a  six- 
mile  radius  on  the  map  of  the  Atlantic,  you 
will  find  that  it  is  a  mere  speck  in  the  ocean; 
but  a  U-boat  commander  could  see  objects 
that  lay  far  beyond  his  horizon  because  he  was 
searching  for  objects  which  towered  many  feet 
above  the  water.  The  smoke-stacks  of  some 
vessels  rise  a  hundred  feet  above  the  water- 
line,  and  the  masts  reach  up  to  much  greater 
altitudes.  Aside  from  this,  in  the  early  days 
of  the  war  steamers  burned  soft  coal  and  their 
funnels  belched  forth  huge  columns  of  smoke 
which  was  visible  from  twenty  to  thirty  miles 
away. 

When  this  was  realized,  efforts  were  made 
to  cut  down  the  superstructure  of  a  ship  as  much 
as  possible.  Some  vessels  had  their  stacks 
cut  down  almost  to  the  deck-line,  and  air-pumps 
were  installed  to  furnish  the  draft  necessary  to 


220      INVENTIONS  OF  THE  GREAT  WAR 

keep  their  furnaces  going.  They  had  no  masts 
except  for  slender  iron  pipes  which  could  be 
folded  down  against  the  deck  and  could  be 
erected  at  .a  moment's  notice,  to  carry  the 
aerials  of  the  wireless  system.  Over  the  ship 
from  stem  to  stern  was  stretched  a  cable, 
familiarly  known  as  a  "  clothes-line, "  upon 
which  were  laid  strips  of  canvas  that  com- 
pletely covered  the  superstructure  of  the  ship. 
These  boats  lay  so  low  that  they  could  not  be 
seen  at  any  great  distance,  and  it  was  difficult 
for  the  U-boats  to  find  them.  They  were  slow 
boats;  too  slow  to  run  away  from  a  modern 
submarine,  but  because  of  their  lowly  structure, 
they  managed  to  elude  the  German  U-boats. 
When  they  were  seen,  the  U-boat  commanders 
were  afraid  of  them.  They  were  suspicious  of 
anything  that  looked  out  of  the  ordinary,  and 
preferred  to  let  the  "  clothes-line  ships "  go. 

THE   BRITISH   MYSTERY   SHIPS 

The  Germans  had  some  very  unhealthy  ex- 
periences with  the  "Q-boats"  or  "mystery 
ships "  of  the  British.  These  were  vessels 
rigged  up  much  like  ordinary  tramp  steamers, 
but  they  were  loaded  with  wood,  so  that  they 


WARRIORS  OF  THE  PAINT-BRUSH      221 

would  not  sink,  and  their  hatches  were  arranged 
to  fall  open  at  the  touch  of  a  button,  exposing 
powerful  guns.  They  also  were  equipped  with 
torpedo-tubes,  so  that  they  could  give  the  U-boat 
a  dose  of  its  own  medicine.  These  ships  would 
travel  along  the  lanes  frequented  by  submarines, 
and  invite  attack.  They  would  limp  along  as 
if  they  had  been  injured  by  a  storm  or  a  U-boat 
attack,  and  looked  like  easy  prey.  When  a  sub- 
marine did  attack  them,  they  would  send  out 
frantic  calls  for  help,  and  they  had  so-called 
1  panic ' '  parties  which  took  to  the  boats.  Mean- 
time, a  picked  crew  remained  aboard,  carefully 
concealed  from  view,  and  the  captain  kept  his 
eye  upon  the  enemy  through  a  periscope  dis- 
guised as  a  small  ventilator,  waiting  for  the 
U-boat  to  come  within  range  of  certain  destruc- 
tion. Sometimes  the  panic  party  would  lure 
the  submarine  into  a  favorable  position  by 
rowing  under  the  stern  as  if  to  hide  around  the 
other  side  of  the  ship.  At  the  proper  moment, 
up  would  go  the  white  ensign — the  British 
man-of-war  flag — the  batteries  would  be  un- 
masked, and  a  hail  of  shell  would  break  loose 
over  the  Hun.  Many  a  German  submarine  was 
accounted  for  by  such  traps. 


222      INVENTIONS  OF  THE  GREAT  WAR 

Submarines  themselves  used  all  sorts  of 
camouflage.  They  were  frequently  equipped 
with  sails  which  they  would  raise  to  disguise 
themselves  as  peaceful  sloops,  and  in  this  way 
they  were  able  to  steal  up  on  a  victim  without 
discovery.  Sometimes  they  would  seize  a  ship 
and  hide  behind  it  in  order  to  get  near  their 
prey. 

CAMOUFLAGE   ON    LAND 

But  the  call  for  the  wielders  of  the  paint- 
brush came  not  only  from  the  sea.  Their  ser- 
vices were  needed  fully  as  much  on  land,  and  the 
making  of  land  camouflage  was  far  more  in- 
teresting because  it  was  more  varied  and  more 
successful.  Besides,  it  called  for  more  than 
mere  paint;  all  sorts  of  tricks  with  canvas, 
grass,  and  branches  were  used.  Of  course,  the 
soldiers  were  garbed  in  dust-colored  clothing 
and  shiny  armor  was  discarded.  The  helmets 
they  wore  were  covered  with  a  material  that  cast 
no  gleam  of  light.  In  every  respect,  they  tried 
to  make  themselves  of  the  same  shade  as  their 
surroundings.  Like  the  Indians,  they  painted 
their  faces.  This  was  done  when  they  made 
their  raids  at  night.  They  painted  their  faces 


WARRIORS  OF  THE  PAINT-BRUSH     223 

black  so  that  they  would  not  show  the  faintest 
reflection  of  light. 

A   PAPEB    HOESE 

The  most  interesting  camouflage  work  was 
done  for  the  benefit  of  snipers  or  for  observers 
at  listening-posts  close  to  the  enemy  trenches. 
It  was  very  important  to  spy  on  the  enemy  and 
discover  his  plans,  and  so  men  were  sent  out 
as  near  his  lines  as  possible,  to  listen  to  the  con- 
versation and  to  note  any  signs  of  unusual  ac- 
tivity which  would  be  likely  to  precede  a  raid. 
These  men  were  supplied  with  telephone  wires 
which  they  dragged  over  No  Man's  Land,  and 
by  which  they  could  communicate  their  dis- 
coveries to  headquarters.  Some  very  ingenious 
listening-posts  were  established.  In  one  case 
a  papier-mache  duplicate  of  a  dead  horse  was 
made,  which  was  an  exact  facsimile  of  an  ani- 
mal that  had  been  shot  and  lay  between  the  two 
lines.  One  night,  the  carcass  of  the  horse  was 
removed  and  the  papier-mache  replica  took  its 
place.  In  the  latter  a  man  was  stationed  with 
telephone  connection  back  to  his  own  lines. 
Here  he  had  an  excellent  chance  to  watch  the 
enemy. 


224      INVENTIONS  OF  THE  GREAT  WAR 

On  another  occasion  a  standing  tree,  whose 
branches  had  been  shot  away,  was  carefully 
photographed  and  an  exact  copy  of  it  made,  but 
with  a  chamber  inside  in  which  an  observer  could 
be  concealed.  One  night  while  the  noise  of  the 
workmen  was  drowned  by  heavy  cannonading, 
this  tree  was  removed  and  its  facsimile  was  set 
up  instead,  and  it  remained  for  many  a  day  be- 
fore the  enemy  discovered  that  it  was  a  fake 
tree-trunk.  It  provided  a  tall  observation  post 
from  which  an  observer  could  direct  the  fire  of 
his  own  artillery. 

FOOLING    THE   WATCHERS   IN    THE   SKY 

In  the  early  stages  of  the  war,  it  seemed  im- 
possible to  hide  anything  from  the  Germans. 
They  had  eyes  everywhere  and  were  able  to  an- 
ticipate everything  the  Allies  did.  But  the 
spies  that  infested  the  sky  were  the  worst  handi- 
cap. Even  when  the  Allies  gained  control  of 
the  air,  the  control  was  more  or  less  nominal 
because  every  now  and  then  an  enemy  observer 
would  slip  over  or  under  the  patrolling  aero- 
planes and  make  photographs  of  the  Allies' 
lines.  The  photographs  were  carefully  com- 


WARRIORS  OF  THE  PAINT-BRUSH     225 

pared  with  others  previously  taken,  that  the 
slightest  change  in  detail  might  be  discovered. 
Airplane  observers  not  only  would  be  ready 
to  drop  bombs  on  any  suspicious  object  or  upon 
masses  of  troops  moving  along  the  roads,  but 
would  telephone  back  to  their  artillery  to  direct 
its  fire  upon  these  targets.  Of  course,  the 
enemy  knew  where  the  roads  were  located  and 
a  careful  watch  was  kept  of  them. 

The  French  did  not  try  to  hide  the  roads,  but 
they  concealed  the  traffic  on  the  roads  by  hang- 
ing rows  of  curtains  over  them.  As  these  cur- 
tains hung  vertically  and  were  spaced  apart,  one 
would  suppose  that  they  would  furnish  little 
concealment,  but  they  prevented  an  observer 
in  an  aeroplane  from  looking  down  the  length 
of  a  road.  All  the  road  he  could  see  was  that 
which  lay  directly  under  his  machine,  because 
there  he  could  look  between  the  curtains;  if 
he  looked  obliquely  at  the  road,  the  curtains 
would  appear  to  overlap  one  another  and  would 
conceal  operations  going  on  under  them. 

In  one  case,  the  Germans  completely  covered 
a  sunken  road  with  canvas  painted  to  represent 
a  road  surface.  Under  this  canvas  canopy, 


226      INVENTIONS  OF  THE  GREAT  WAK 

troops  were  moved  to  an  important  strategic 
point  without  the  slightest  indication  of  such  a 
movement. 

HIDING  BIG  GUNS 

Nature 's  tricks  of  camouflage  were  freely  used 
in  the  hiding  of  the  implements  of  war  on  land. 
Our  big  guns  were  concealed  by  being  painted 
with  leopard  spots  and  tiger  stripes,  the  color 
and  nature  of  the  camouflage  depending  upon 
the  station  they  were  to  occupy.  In  many  cases, 
they  were  covered  with  branches  of  trees  or 
with  rope  netting  overspread  with  leaves.  So 
careful  was  the  observation  of  the  air  scouts 
that  even  the  grass  scorched  by  the  fire  of  the 
gun  had  to  be  covered  with  green  canvas  to 
prevent  betrayal  of  the  position  of  the  gun. 

BO  ADS   THAT   LED   NOWHERE 

In  the  making  of  an  emplacement  for  a  gun 
it  was  of  the  utmost  importance  that  no  fresh 
upturned  earth  be  disclosed  to  the  aerial  ob- 
servers. Even  foot-paths  leading  to  it  had  to 
be  concealed.  Plans  were  carefully  made  to 
cover  up  all  traces  of  the  work  before  the  work 
was  begun.  Where  it  was  impossible  to  conceal 


WARRIORS  OF  THE  PAINT-BRUSH     227 

the  paths,  they  were  purposely  made  to  lead 
well  beyond  the  point  where  the  emplacement 
was  building,  and,  still  further  to  deceive  the 
enemy,  a  show  of  work  was  sometimes  under- 
taken at  the  end  of  the  path.  Wherever  the 
sod  had  to  be  upturned,  it  was  covered  over 
with  green  canvas.  The  earth  that  was  re- 
moved had  to  be  concealed  somewhere  and  the 
best  place  of  concealment  was  found  to  be  some 
old  shell-hole  which  would  hold  a  great  deal 
of  earth  without  any  evidence  that  would  be  ap- 
parent to  an  observer  in  an  aeroplane.  If  no 
shell-hole  were  handy,  the  excavated  material 
had  to  be  hauled  for  miles  before  a  safe  dump- 
ing-ground could  be  found.  As  far  as  possible 
everything  was  sunk  below  the  earth  level. 
Big  pits  were  dug  in  which  the  mortars  were 
placed,  or  if  a  shell-hole  were  empty,  this  was 
used  instead. 

SHADOWLESS   BUILDINGS 

Any  projection  above  the  ground  was  apt  to 
cast  a  shadow  which  would  show  up  on  the  ob- 
server's photographs.  This  was  a  difficulty 
that  was  experienced  in  building  the  hangars 
for  airplanes.  The  roofs  of  these  sheds  were 


228      INVENTIONS  OF  THE  GREAT  WAR 

painted  green  so  as  to  match  the  sod  around 
them,  but  as  they  projected  above  their  sur- 
roundings, they  cast  shadows  which  made  them 
clearly  evident  to  the  enemy.  This  was  over- 
come by  the  building  of  shadowless  hangars; 
that  is,  hangars  with  roofs  that  extended  all 
the  way  to  the  ground  at  such  an  angle  that  they 
would  cause  no  shadow  except  when  the  sun  was 
low.  In  some  cases,  aeroplanes  were  housed 
in  underground  hangars,  the  approach  to  which 
was  concealed  by  a  canvas  covering.  As  for 
the  machines  themselves,  they  scorned  the  use 
of  camouflage.  Paint  was  little  protection  to 
them.  Some  attempt  was  made  to  use  trans- 
parent wings  of  cellon,  a  material  similar  to 
celluloid,  but  this  did  not  prove  a  success. 

THE   PHOTOGRAPHIC    BYE 

Although  camoufleurs  made  perfect  imitations 
of  natural  objects  and  surroundings,  they  were 
greatly  concerned  to  find  -that  the  flying  observ- 
ers could  see  through  their  disguises.  To  the 
naked  eye  the  landscape  would  not  show  the 
slightest  trace  of  any  suspicious  object,  but  by 
the  use  of  a  color-screen  to  cut  out  certain  rays 
of  light,  a  big  difference  would  be  shown  between 


WARRIORS  OF  THE  PAINT-BRUSH     229 

the  real  colors  of  nature  and  the  artist's  copies 
of  them.  For  instance,  if  a  roof  painted  to 
look  like  green  grass  were  viewed  through  a 
red  color-screen,  it  would  look  brown ;  while  the 
real  grass,  which  apparently  was  of  exactly  the 
same  shade  as  the  roof,  would  look  red.  It 
had  not  been  realized  by  the  artists  who  had 
never  studied  the  composition  of  light,  that  there 
is  a  great  deal  of  red  in  the  green  light  reflected 
by  grass,  and  that  if  they  were  to  duplicate 
this  shade  of  green,  they  must  put  a  certain 
amount  of  red  paint  in  their  imitation  grass 
roofs.  Air  scouts  did  not  depend  upon  their 
eyes  alone,  but  used  cameras  so  that  they  could 
study  their  photographs  at  their  leisure  and  by 
fitting  the  cameras  with  different  color-screens, 
they  could  analyze  the  camouflage  and  undo  the 
patient  work  of  the  artist. 

A    CALL  FOR   THE   PHYSICIST 

To  meet  this  situation,  another  man  was  sum- 
moned to  help — the  physicist,  who  looks  upon 
color  merely  as  waves  of  ether;  who  can  pick 
a  ray  of  light  to  pieces  just  as  a  chemist  can 
analyze  a  lump  of  sugar.  Under  his  expert 
guidance,  colors  of  nature  were  imitated  so  that 


230      INVENTIONS  OF  THE  GREAT  WAR 

they  would  defy  detection.  Aside  from  this,  the 
physicist  helped  to  solve  the  tricks  of  the 
enemy 's  camoufleurs. 

But  the  physicist  had  barely  rolled  up  his 
sleeves  and  got  into  the  fray  when  the  armis- 
tice was  signed  which  put  an  end  to  the  shams 
as  well  as  to  the  realities  of  the  great  war. 
While  the  work  of  camouflage  was  not  com- 
pleted, we  owe  an  inestimable  debt  to  the  men 
who  knew  how  to  fake  scenery  and  to  their 
learned  associates  who  count  the  wave  lengths 
of  light,  and  although  their  trade  was  a  trade  of 
deception  and  shams,  there  was  no  sham  -about 
the  service  they  rendered. 

MAKING    SHIPS   VISIBLE 

While  in  war  safety  lies  in  invisibility,  in 
peace  the  reverse  is  true.  Now  that  the  war  is 
over,  it  may  seem  that  the  work  of  the  camou- 
fleurs can  find  no  useful  application;  but  it 
was  impossible  to  learn  how  to  make  objects 
invisible  without  also  learning  how  to  make 
them  conspicuously  visible.  As  a  consequence, 
we  know  now  how  to  paint  a  ship  so  that  it 
will  show  up  more  clearly  in  foggy  weather, 
thereby  reducing  the  danger  of  collision.  We 


WARRIORS  OF  THE  PAINT-BRUSH     231 

know,  too,  how  to  paint  light-ships,  buoys,  etc., 
so  that  they  will  be  much  more  conspicuous 
and  better  guides  to  mariners,  and  how  to  color 
railroad  signals  and  road  signs  so  that  they 
will  be  more  easily  seen  by  locomotive  engineers 
and  automobile  drivers. 


OHAPTEE  XII 

SUBMABIIOJS 

IT  was  an  American  invention  that  dragged 
America  into  the  war — an  American  inven- 
tion in  the  hands  of  barbarians  and  put  to  un- 
speakably barbarous  use. 

After  seeing  how  the  Huns  used  the  sub- 
marine we  are  not  so  sure  that  we  can  take  much 
pride  in  its  invention.  But  if  any  blame  at- 
taches to  us  for  developing  the  submarine,  we 
made  amends  by  the  way  in  which  we  fought  the 
German  U-boat  and  put  an  end  to  German 
frightfulness  on  the  sea.  Of  course,  the  credit 
for  Germany's  defeat  is  not  for  a  moment 
claimed  by  Americans  alone,  but  it  must  be  ad- 
mitted that  we  played  an  important  part  in 
overcoming  the  menace  of  the  U-boat. 

There  is  no  question  that  the  submarine  was 
an  American  invention.  To  be  sure,  we  can  look 
into  ancient  books  and  find  suggestions  for  navi- 
gating under  the  surface  of  the  sea,  but  the 

232 


SUBMARINES  233 

first  man  who  did  actually  build  «a  successful 
submarine  was  David  Bushnell,  back  in  the 
Revolutionary  War.  After  him  came  Robert 
Fulton,  who  carried  the  invention  farther.  He 
built  and  operated  a  submarine  for  the  French 
Government,  and,  in  more  recent  years,  the  sub- 
marine became  a  practical  vessel  of  war  in  the 
hands  of  John  P.  Holland  and  Simon  Lake, 
both  Americans.  However,  we  are  not  inter- 
ested, just  now,  in  the  history  of  the  submarine, 
but  rather  in  the  development  of  this  craft 
during  the  recent  war. 

With  Great  Britain  as  an  enemy,  Germany 
knew  that  she  was  hopelessly  outclassed  on  the 
sea;  but  while  "Britannia  ruled  the  waves,"  she 
did  not  rule  the  depths  of  the  sea,  and  so  Ger- 
many decided  to  claim  this  realm  for  her  own. 
Little  attention  did  she  pay  to  surface  vessels. 
Except  in  the  Dogger  Bank  engagement  and  the 
Battle  of  Jutland,  the  German  first-class  ves- 
sels did  not  venture  out  upon  the  open  sea,  and 
even  the  lighter  craft  merely  made  occasional 
raids  under  cover  of  fog  or  darkness,  only 
to  cut  and  run  as  soon  as  the  British  vessels 
appeared.  The  submarine  boat,  or  untersee- 
boot  as  the  Germans  called  it,  was  virtually  the 


234      INVENTIONS  OF  THE  GREAT  WAR 

only  boat  that  dared  go  out  into  the  high  seas ; 
consequently,  the  Germans  specialized  upon 
that  type  of  craft  and  under  their  close  atten- 
tion it  grew  into  a  highly  perfected  war-vessel. 
But  the  Germans  were  not  the  only  ones  to  de- 
velop the  submarine,  as  we  shall  see. 

CONSTRUCTION    OF   THE   U-BOATS 

When  the  great  war  broke  out,  the  German  U- 
boat  was  a  comparatively  small  craft,  less  than 
150  feet  long,  with  its  main  hull  only  12  feet  in 
diameter.  It  could  make  a  speed  of  12  knots  on 
the  surface  and  only  9  when  submerged.  But 
as  the  war  progressed,  it  grew  larger  and 
larger,  until  it  attained  a  length  of  over  300 
feet  and  its  speed  was  increased  to  12  knots 
when  submerged  and  18  knots  on  the  surface. 

Figs.  16  to  18  show  the  construction  of  one 
of  the  early  U-boats.  The  later  boats  were 
built  after  the  same  general  plan,  but  on  a 
bigger  scale. 

It  is  not  always  safe  to  judge  a  thing  by  its 
name;  to  do  so  is  apt  to  lead  to  sad  mistakes. 
One  would  naturally  suppose,  from  its  name, 
that  a  submarine  is  a  boat  that  lives  under 
water,  like  a  fish.  But  i<t  is  not  a  fish;  it  is 


235 


236      INVENTIONS  OF  THE  GREAT  WAR 

an  air-breathing  animal  that  prefers  to  stay 
on  the  surface,  only  occasionally  diving  under  to 
hide  from  danger  or  to  steal  upon  its  prey. 
During  the  war,  the  German  U-boats  did  not 
average  three  hours  per  day  under  the  surface ! 
Because  they  were  intended  to  run  on  the  sur- 
face they  had  to  be  built  in  the  form  of  a  sur- 
face vessel,  so  as  to  throw  off  the  waves  and 
keep  from  rolling  and  pitching  too  much  in  a 
seaway.  But  they  also  had  to  be  built  to  with- 
stand the  crushing  weight  of  deep  water,  and  as 
a  cylinder  is  much  stronger  than  a  structure  of 
ordinary  boat  shape,  the  main  hull  was  made  cir- 
cular in  section  and  of  heavy  plating,  strongly 
framed,  while  around  this  was  an  outer  hull 
of  boat  shape,  as  shown  in  Fig.  18. 

PUTTING   HOLES   IN    A    TANK    TO   KEEP   IT   FULL, 

The  space  between  the  inner  and  outer 
hulls  was  used  for  water  ballast  and  for  reser- 
voirs of  oil  to  drive  the  engines;  and,  strange 
as  it  may  seem,  the  oil-tanks  were  always  kept 
full  by  means  of  holes  in  the  bottom  of  them. 
As  the  oil  was  consumed  by  the  engines,  water 
would  flow  into  the  reservoir  to  take  its  place, 
and  the  oil,  being  lighter  than  water,  would  float 


:: —         _r-^r-r^-=j       jr        INNCB  CIRCULAR  j       f^-=^=—-—-=i^ 


Courtesy  of  the   "Scientific   American" 

FIG.  18.  Transverse  section  through  conning-tower,  showing 
the  interior  (circular)  pressure-resisting  hull  and  the 
lighter  exterior  hull,  which  is  open  to  the  sea 


237 


238      INVENTIONS  OF  THE  GREAT  WAR 

on  top.  The  false  hull  was  of  light  metal,  be- 
cause as  it  was  open  to  the  sea,  the  pressure  on 
the  inside  was  always  the  same  as  that  on  the 
outside.  The  reservoirs  of  oil  and  the  water- 
ballast  tanks  protected  the  inner  hull  of  the 
vessel  from  accidental  damage  and  from  hostile 
shell  and  bombs.  There  were  water-ballast 
tanks  inside  the  inner  hull  as  well,  as  shown  in 
the  cross-sectional  view,  Fig.  18.  The  water 
in  the  ballast-tanks  was  blown  out  by  com- 
pressed air  to  lighten  the  U-boat  and  the  boat 
was  kept  on  an  even  keel  by  the  blowing  out 
or  the  letting  in  of  water  in  the  forward  and 
after  tanks. 

A  heavy  lead  keel  was  attached  to  the  bottom 
of  the  boat,  to  keep  it  from  rolling  too  mudh. 
In  case  of  accident,  if  there  were  no  other  way  of 
bringing  the  boat  to  the  surface,  this  keel  could 
be  cast  loose. 

At  the  forward  end,  where  the  torpedo-tubes 
were  located,  there  was  a  torpedo-trimming 
tank.  Torpedoes  are  heavy  missiles  and  every 
time  one  was  discharged  the  boat  was  lightened, 
and  the  balance  of  the  submarine  was  upset. 
To  make  up  for  the  loss  of  weight,  water  had 
to  be  let  into  the  torpedo-trimming  tank. 


SUBMARINES  239 

A  submarine  cannot  float  under-water  "With- 
out swimming ;  in  other  words,  it  must  keep  its 
propellers  going  to  avoid  either  sinking  to  the 
bottom  of  the  sea  or  bobbing  up  to  the  surface. 
To  be  sure,  it  can  make  itself  heavier  or  lighter 
by  letting  water  into  or  blowing  water  out  of 
its  ballast-tanks,  but  it  is  impossible  to  regulate 
the  water  ballast  so  delicately  that  the  sub- 
marine will  float  submerged;  and  should  the 
boat  sink  to  a  depth  of  two  hundred  feet  or  so, 
the  weight  of  water  above  it  would  be  suffi- 
cient to  crush  the  hull,  so  it  is  a  case  of  sink 
or  swim.  Usually  enough  ballast  is  taken  on 
to  make  the  submarine  only  a  little  lighter  than 
the  water  it  displaces ;  and  then  to  remain  under, 
the  vessel  must  keep  moving,  with  its  hori- 
zontal rudders  tilted  to  hold  it  down.  The  hori- 
zontal rudders  or  hydroplanes  of  the  U-boat 
are  shown  in  Fig.  17,  both  at  the  bow  and  at 
the  stern. 

The  main  hull  of  'the  vessel  was  literally  filled 
with  machinery.  In  the  after  part  of  the  boat 
were  the  Diesel  oil-engines  with  which  the 
U-boat  was  propelled  when  on  the  surface. 
There  were  two  engines,  each  driving  a  pro- 
peller-shaft. It  was  impossible  to  use  the  en- 


240      INVENTIONS  OF  THE  GREAT  WAR 

gines  when  the  vessel  was  submerged,  not  be- 
cause of  the  gases  they  produced — these  could 
easily  have  been  carried  out  of  the  boat — but 
because  every  internal-combustion  engine  cqn- 
sumes  enormous  quantities  of  air.  In  a  few 
minutes  the  engines  would  devour  all  the  air 
in  the  hull  of  the  submarine  and  would  then 
die  of  suffocation.  And  so  the  engines  were 
used  only, when  the  submarine  was  running 
awash  or  on  the  surface,  and  then  the  air  con- 
sumed by  them  would  rush  down  the  hatchway 
like  a  hurricane  to  supply  their  mighty  lungs. 

ENGINES   THAT   BUEN    HEAVY   OIL. 

The  oil-engines  were  strictly  a  German  in- 
vention. In  the  earlier  days  of  the  submarine 
gasolene-engines  were  used,  but  despite  every 
precaution,  gasolene  vapors  occasionally  would 
leak  out  of  the  reservoirs  and  accumulate  in 
pockets  or  along  the  floors  of  the  hull,  and  it 
needed  but  a  spark  to  produce  an  explosion 
that  would  blow  up  the  submarine.  But 
Eudolph  Diesel,  a  German,  invented  an  engine 
which  would  burn  'heavy  oils. 

In  the  Diesel  engine  there  are  no  spark-plugs 
and  no  magneto:  the  engine  fires  itself  with- 


SUBMARINES  241 

out  electrical  help.     Air  is  let  into  the  cylinder 
at  ordinary  atmospheric  pressure,   or  fifteen 
pounds  per  square  inch.    But  it  is  compressed 
by  the  upward  stroke  of  the  piston  to  about 
five  hundred  pounds  per  square  inch.    When 
air  is  compressed  it  develops  heat  and  the  sud- 
den high  compression  to  over  thirty  times  its 
normal  pressure  raises  the  temperature  to  some- 
thing like  1000  degrees  Fahrenheit.     Just  as 
this  temperature  is  reached,  a  jet  of  oil  is  blown 
into  the  cylinder  by  air  under  still  higher  pres- 
sure.   Immediately  the  spray  of  oil  bursts  into 
flame  and  the  hot  gases  of  combustion  drive  the 
piston  down.    Because  of  the  intense  heat  al- 
most any  oil,  from  light  gasolene  to  heavy,  al- 
most tarlike  oils,  can  be  used.    As  heavy  oils 
do  not  throw  off  any  explosive  vapors  unless 
they  are  heated,  they  make  a  very  safe  fuel  for 
submarines. 

To  drive  the  U-boat  when  no  air  was  to  be  had 
for  the  engines,  electric  motors  were  used. 
There  was  one  on  each  propeller-shaft  and  the 
shafts  could  be  disconnected  from  the  oil-en^ 
gines  when  the  motors  were  driving.  The  mo- 
tors got  their  power  from  storage  batteries  in 
the  stern  of  the  submarine  and  under  the  floors 


242      INVENTIONS  OF  THE  GBEAT  WAR 

forward.  The  motors  when  coupled  to  and 
driven  by  the  engines  generated  current  which 
was  stored  in  the  storage  batteries.  The  sub- 
marine could  not  run  on  indefinitely  under- 
water. When  its  batteries  were  exhausted  it 
would  have  to  come  to  the  surface  and  run  its 
engines  to  store  up  a  fresh  charge  of  electricity. 
The  electric  motors  gave  the  boat  a  speed  of 
about  nine  knots. 

In  addition  to  the  main  engines  and  motors, 
there  was  a  mass  of  auxiliary  machinery. 
There  were  pumps  for  compressing  air  to  blow 
the  ballast-tanks  and  to  discharge  the  torpedoes. 
There  was  a  special  mechanism  for  operating 
the  rudder  and  hydroplanes,  and  all  sorts  of 
valves,  indicators,  speaking-tubes,  signal  lines, 
etc.  The  tiny  hull  was  simply  crammed  with 
mechanism  of  all  kinds  and  particularly  in  the 
early  boats  there  was  little  room  for  the  accom- 
modation of  the  officers  and  crew.  The  officers ' 
quarters  were  located  amidships,  and  forward 
there  were  the  folding  berths  of  the  crews.  In 
the  later  boats  more  space  was  given  the  men. 
The  large  U-boats  carried  a  crew  of  forty  and 
as  the  hazards  of  submarine  warfare  increased, 
more  attention  had  to  be  paid  to  the  men. 


SUBMARINES  243 

FAT    MEN    NOT   WANTED 

Oddly  enough,  small,  slender  men  were  pre- 
ferred for  submarine  duty,  not  because  of  lack 
of  space,  but  because  it  was  apt  to  be  very  cold 
in  a  submarine,  particularly  in  the  winter-time. 
The  water  cooled  off  the  boat  when  the  sub- 
marine was  traveling  submerged,  and  the  motors 
gave  off  little  heat;  while  when  the  vessel  was 
running  on  the  surface  the  rush  of  wind  to  sup- 
ply the  engines  kept  the  thermometer  low.  This 
meant  that  the  men  had  to  pile  on  much  clothing 
to  keep  warm,  which  made  them  very  bulky. 
The  hatchway  was  none  too  large -and  a  fat  man, 
were  he  bundled  up  with  enough  clothing  to  keep 
him  warm,  would  have  a  hard  time  squeezing 
through. 

In  the  center  of  the  vessel  was  the  main  hatch- 
way, leading  up  to  the  conning-tower,  which 
was  large  enough  to  hold  from  three  to  five  men. 
This  was  the  navigating-room  when  the  vessel 
was  running  submerged,  and  above  it  was  the 
navigating-bridge,  used  when  the  -submarine 
was  on  the  surface.  In  the  conning-tower  there 
was  a  gyroscopic  compass ;  a  magnetic  compass 
would  not  work  at  all  inside  the  -steel  hull  of 


244      INVENTIONS  OF  THE  GREAT  WAR 

the  U-boat.  And  here  were  .the  periscopes  or 
eyes  of  the  submarine,  rising  from  fifteen  to 
twenty  feet  above  the  roof  of  the  conning- 
tower.  There  were  usually  two  periscopes. 
They  could  be  turned  around  to  give  the 
man  at  the  wheel  a  view  in  any  direction  and 
they  were  used  sometimes  even  when  the  vessel 
was  running  on  the  surface,  to  give  a  longer 
range  of  vision. 

THE   BLINDNESS   OF    THE    SUBMAKINE 

Now,  a  submarine  cannot  see  anything  under- 
water. The  commander  cannot  even  see  the 
bow  of  his  boat  from  the  conning-tower,  and 
until  he  gets  near  enough  to  the  surface  to 
poke  his  periscope  out  of  water  he  is  absolutely 
blind  and  must  feel  his  way  about  with  compass 
and  depth-gage.  It  was  always  an  anxious  mo- 
ment for  the  U-boat  commander,  when  he  was 
coming  up,  until  his  periscope  broke  out  of  the 
water  and  he  could  get  his  bearings ;  and  even 
that  was  attended  with  danger,  for  his  peri- 
scope might  be  seen.  Of  course  a  periscope 
is  a  very  insignificant  object  on  the  broad  sea, 
but  when  a  submarine  is  moving  its  periscope 
is  followed  by  a  wake  which  is  very  conspic- 


SUBMARINES  245 

uous,  and  so  the  U-boat  ran  a  chance  of  being 
discovered  and  destroyed  before  it  could  dive 
again  to  a  safe  depth.  Later,  telescoping  peri- 
scopes were  used,  which  could  be  raised  by 
means  of  a  hand-lever.  The  submarine  would 
run  along  just  under  the  surface  and  every 
now  and  then  it  would  suddenly  raise  its  peri- 
scope for  an  observation  and  drop  it  down  again 
under  cover  if  there  was  danger  nigh.  This 
was  much  simpler  and  quicker  than  having  a  six- 
or  eight-hundred-ton  boat  -come  up  to  the  sur- 
face and  dive  to  safety.  He  might  even  collide 
with  a  vessel  floating  on  the  surface,  but  to 
lessen  this  danger  submarines  were  furnished 
with  ears  or  big  microphone  diaphragms  at  each 
side  of  the  hull  by  which  a  ship  could  be  located 
by  the  noise  of  its  propellers. 

In  the  bow  were  the  torpedo-tubes  and  the 
magazine  of  torpedoes.  At  first  there  were  only 
two  torpedo-tubes,  but  later  the  number  was 
increased  to  four.  These  were  kept  constantly 
loaded,  so  that  the  projectiles  could  be  launched 
in  rapid  succession,  if  necessary,  without  a 
p*ause  for  the  insertion  of  a  fresh  torpedo.  In 
some  submarines  tubes  were  provided  in  the 
stern  also  so  that  the  boat  could  discharge  a 


246     INVENTIONS  OF  THE  GREAT  WAR 

torpedo  at  its  enemy  while  running  away  from 
him. 

Each  tube  was  closed  at  the  outer  end  by  a 
cap  and  art  the  inside  end  by  a  breech-block. 
The  tube  was  blown  clear  of  water  by  means  of 
compressed  air,  and  of  course  the  outer  cap  was 
closed  when  the  breech  was  open  to  let  in  a  tor- 
pedo. Then  the  breech  was  closed,  the  cap 
opened,  and  the  torpedo  was  discharged  from 
the  tube  by  a  blast  of  air. 

THE   TORPEDO 

A  torpedo  is  really  a  motor-boat,  a  won- 
derfully constructed  boat,  fitted  with  an  en- 
gine of  its  own  that  is  driven  by  compressed 
air  and  which  drives  the  torpedo  through  the 
water  at  about  forty  miles  per  hour.  The 
motor-boat  is  shaped  like  a  cigar  and  that 
used  by  the  Germans  was  about  fifteen  feet 
long  and  fourteen  inches  in  diameter.  We 
used  much  larger  torpedoes,  some  of  them 
being  twenty-two  feet  long.  Ours  have  a  large 
compressed-air  reservoir  and  will  travel  for 
miles;  but  the  Germans  used  their  torpedoes 
at  short  ranges  of  a  thousand  yards  and  under, 
cutting  down  the  air-reservoir  as  much  as  pos- 


SUBMARINES  247 

sible  and  loading  the  torpedo  with  an  extra 
large  explosive  charge. 

We  found  in  the  Diesel  engine  that  when 
air  is  highly  compressed  it  becomes  very 
hot.  When  compressed  air  is  expanded,  the 
reverse  takes  place,  the  air  becomes  very  cold. 
The  air  that  drives  the  motor  of  the  torpedo 
grows  so  cold  that  were  no  precautions  taken 
it  would  freeze  any  moisture  that  might  be 
present  and  would  choke  up  the  engine  with  the 
frost.  And  so  an  alcohol  flame  is  used  to  heat 
the  air.  The  air-motor  is  started  automatically 
by  release  of  a  trigger  as  the  torpedo  is  blown 
out  of  the  torpedo-tube.  By  means  of  gear- 
ing, the  motor  drives  two  propellers.  These  run 
in  opposite  directions,  so  as  to  balance  each 
other  and  prevent  any  tendency  for  the  torpedo 
to  swerve  from  its  course.  The  torpedo  is 
steered  by  a  rudder  which  is  controlled  by  a 
gyroscope,  and  it  is  kept  at  the  proper  depth 
under  water  by  diving-rudders  which  are  con- 
trolled by  a  very  sensitive  valve  worked  by  the 
weight  of  the  water  above  it.  The  deeper  the 
water,  the  greater  the  weight  or  pressure;  and 
the  valve  is  so  arranged  that,  should  the  tor- 
pedo run  too  far  under,  the  pressure  will  cause 


248      INVENTIONS  OF  THE  GREAT  WAR 

the  diving-rudders  to  tilt  until  the  torpedo  comes 
up  again ;  then  if  the  torpedo  rises  too  high,  the 
valve  will  feel  the  reduction  of  pressure  and 
turn  the  rudders  in  the  other  direction. 

The  business  end  of  a  torpedo  is  a  " war- 
head "  packed  with  about  four  hundred 
pounds  of  TNT.  At  the  nose  of  the  tor- 
pedo is  a  firing-pin,  with  which  the  war-head 
is  exploded.  Ordinarily,  the  firing-pin  does 
not  project  from  the  torpedo,  but  there  is  a 
little  propeller  at  the  forward  end  which  is 
turned  by  the  rush  of  water  as  the  torpedo 
is  driven  on  its  course.  This  draws  out  the 
firing-pin  and  gets  everything  ready  for  the 
TNT  to  explode  as  soon  as  the  firing-pin  is 
struck.  But  the  firing-pin  is  not  the  only  means 
of  exploding  the  torpedo.  Inside  there  is  a  very 
delicate  mechanism  that  will  set  off  the  charge 
at  the  least  provocation.  In  one  type  of  tor- 
pedo a  steel  ball  is  provided  which  rests  in  a 
shallow  depression  and  the  slightest  shock,  the 
sudden  stopping  or  even  a  sudden  swerve  of  the 
torpedo,  would  dislodge  the  ball  and  set  off  the 
charge.  Hence  various  schemes,  proposed  by 
inventors,  for  deflecting  a  torpedo  without 
touching  the  firing  pin,  would  have  been  of  no 
value  at  all. 


SUBMAKIKETS5  249 

GUNS   ON   SUBMABINES 

As  torpedoes  are  expensive  things,  the 
U-boats  were  supplied  with  other  means  of 
destroying  their  victims.  The  Germans  sprang 
a  surprise  by  mounting  guns  on  the  decks  of 
their  submarines.  At  first  these  were  arranged 
to  be  lowered  into  a  hatch  when  the  boat  was 
running  submerged,  but  later  they  were  per- 
manently mounted  on  the  decks  so  that  they 
would  be  ready  for  instant  use.  They  were 
heavily  coated  with  grease  and  the  bore  was 
swabbed  out  immediately  when  the  boat  came  to 
the  surface,  so  that  there  was  no  danger  of 
serious  rust  and  corrosion.  The  3-inch  gun  of 
the  early  months  of  the  war  soon  gave  way  to 
heavier  pieces  and  the  latest  U-boats  were  sup- 
plied with  guns  of  almost  6-inch  caliber  and 
there  was  a  gun  on  the  after  deck  as  well  as 
forward. 

The  U-boats  depended  upon  radiotelegraphy 
to  get  their  orders  and  although  they  did  not 
have  a  very  wide  sending-range,  they  could  re- 
ceive messages  from  the  powerful  German  sta- 
tion near  Berlin.  The  masts  which  carried  the 
radio  aerials  could  be  folded  down  into  pockets 


250      INVENTIONS  OF  THE  GREAT  WAR 

in  the  deck.  From  stem  to  stern  over  the  entire 
boat  a  cable  was  stretched  which  was  intended  to 
permit  the  U-boat  to  slide  under  nets  protect- 
ing harbor  entrances,  and  in  later  boats  -there 
were  keen-toothed  knives  at  the  bow  which 
would  cut  through  a  steel  net.  During  the  war 
German  and  Austrian  U-boats  occupied  so  much 
attention  that  the  public  did  not  realize  the 
part  that  the  Entente  Allies  were  playing  under 
the  sea.  America,  Great  Britain,  France,  and 
Italy  made  good  use  of  submarines,  operating 
them  against  enemy  vessels,  blockading  enemy 
ports,  and  actually  fighting  enemy  submarines. 

A   STEAM-DRIVEN    SUBMARINE 

The  British  in  particular  did  splendid  work 
with  the  submarine  and  developed  boats  that 
were  superior  to  anything  turned  out  by  the 
Germans.  For  instance,  they  developed  a  sub- 
marine which  is  virtually  a  submersible  de- 
stroyer. It  is  340  feet  long  and  it  can  make  a 
speed  of  24  knots  on  the  surface.  The  most 
remarkable  part  of  this  boat  is  that  its  engines 
are  driven  by  steam.  Its  boilers  are  fired  with 
oil  fuel.  There  are  two  smoke-stacks  which  fold 
(Jown  when  it  submerges.  Of  course  when  run- 


SUBMARINES  261 

ning  under-water  the  vessel  is  driven  by  elec- 
tricity and  it  makes  a  speed  of  10  knots.  It 
carries  three  4^inch  guns,  two  forward  and  one 
aft,  and  its  displacement  submerged  is  2700  tons 
as  against  800  tons  for  the  largest  German  sub- 
marines. 

A    SUBMARINE    THAT    MOUNTS   A   TWELVE-INCH 
GUN 

Still  more  remarkable  is  the  big  "super-sub- 
marine" designed  by  the  British  to  bombard  the 
forts  of  the  Dardanelles,  but  unfortunately  it 
was  built  too  late  to  be  used  there.  This  sub- 
marine carries  a  gun  big  enough  for  a  battle- 
ship. It  is  of  12-inch  caliber  and  weighs  50 
tons.  Of  course  a  big  gun  like  that  could  not 
be  fired  athwart  the  submarine.  It  might  bowl 
the  little  vessel  over,  even  though  it  was  a 
1700-ton  submarine.  The  gun  is  mounted  to 
fire  fore  and  aft,  with  a  deviation  of  only  a  few 
degrees  to  one  side  or  the  other,  so  that  the 
shock  of  the  recoil  is  taken  by  the  length  in- 
stead of  the  beam  of  the  submarine.  It  fires  a 
shell  weighing  620  pounds  and  a  full  charge  is 
not  used,  so  that  the  extreme  range  is  only 
about  15,000  yards.  This  submarine  monitor 


252      INVENTIONS  OF  THE  GREAT  WAR 

would  have  been  a  very  difficult  target  for  the 
Turkish  gunners  to  hit. 

When  the  war  came  to  an  end  and  the  Ger- 
man submarines  surrendered  to  the  Entente 
Allies  at  Harwich,  there  was  considerable 
public  curiosity  as  to  whether  or  not  an  exami- 
nation of  the  U-boats  would  disclose  any 
wonderful  secrets.  But  they  contained  nothing 
that  the  Allies  did  not  already  know,  and  one 
British  officer  stated  that  the  plans  of  the  Ger- 
man submarines  had  often  fallen  into  their 
hands  long  before  a  U-boat  of  the  same  type 
was  captured! 


CHAPTER  XIH 

GETTING  THE  BEST  OF  THE  U-BoAT 

THE  U-boat  commander  who  sallied  forth 
from  the  harbor  of  Wilhelmshaven  in  the 
early  days  of  the  war  had  nothing  to  fear.  He 
was  out  to  murder,  not  to  fight.  His  prey  was 
always  out  in  the  open,  while  he  could  kill  with- 
out exposing  more  than  his  eye  above  water. 
Not  even  a  sporting  chance  was  allowed  his 
victims,  particularly  when  he  chose  unarmed 
merchantmen  for  his  targets.  He  could  come 
up  boldly  to  the  surface  and  shell  a  ship  into 
submission.  This  was  cheaper  than  torpedo- 
ing the  vessel,  because  torpedoes  are  expensive. 
If  the  ship  were  speedy  it  might  run  away;  or 
if  the  U-boat  came  up  too  close  to  its  intended 
prey,  the  latter  might  run  it  down.  That  hap- 
pened occasionally  and  it  was  the  only  danger 
that  the  Herr  Kommandant  had  to  fear. 

If  a  destroyer  suddenly  appeared,  the  U-boat 
could  dive  into  the  shelter  of  the  sea.    If  the 

253 


254      INVENTIONS  OF  THE  GREAT  WAR 

water  were  not  too  deep,  it  could  lie  on  the 
bottom  for  two  or  more  days  if  need  be.  There 
was  plenty  of  air  in  the  hull  to  sustain  life 
for  many  hours  and  then  the  compressed  air 
used  for  blowing  the  ballast-tanks  could  be 
drawn  upon.  In  the  U-boat  there  were  potash 
cartridges  to  take  up  the  carbon-dioxide,  and 
tanks  of  pure  oxygen  to  revitalize  the  air.  If 
the  submarine  were  damaged,  it  was  not  neces- 
sary for  it  to  come  to  the  surface  to  effect  re- 
pairs. There  were  air-locks  through  which  a 
diver  could  be  let  out  of  the  boat.  He  was 
fitted  with  oxygen  and  potash  cartridges,  so 
that  he  did  not  need  to  be  connected  by  an  air- 
hose  with  the  boat,  but  could  walk  around  it 
freely  to  mend  injured  rudders  or  to  clear  the 
propeller  of  entanglements. 

Even  the  small  submarines  of  those  early 
days  were  capable  of  taking  long  voyages. 
Setting  his  course  at  a  comfortable  pace  of  10 
knots,  the  U-boat  commander  could  count  on 
enough  fuel  to  carry  him  1600  miles,  and  if 
need  be  he  could  slow  down  to  8  knots  and  by 
using  certain  of  his  water-ballast  tanks  for 
additional  oil-reservoirs,  extend  his  cruising- 
radius  to  nearly  3000  miles.  The  big  800-ton 


GETTING  THE  BEST  OF  THE  U-BOAT     255 

U-boats  that  were  built  later  had  a  radius  of 
5000  miles  at  an  8-knot  speed.  And  so  when 
the  British  closed  the  English  Channel  with 
nets  and  mines,  Herr  Kommandant  was  not  at 
all  perturbed;  he  could  sail  around  the  British 
Isles  if  he  chose  and  make  war  upon  trans- 
atlantic shipping.  When  harbors  were  walled 
off  with  nets,  he  could  remain  outside  and  sink 
vessels  that  were  leaving  or  entering  them. 

SUBMAKINE-CHASEES 

A  real  menace  came  when  the  U-boat  com- 
mander popped  his  periscope  out  of  the  sea 
and  saw  several  little  motor-boats  bearing  down 
upon  him.  They  seemed  harmless  enough,  but 
a  moment's  inspection  showed  them  to  be  armed 
with  guns  fully  as  powerful  as  those  he  carried. 
It  was  useless  to  discharge  a  torpedo  at  so 
speedy  and  small  a  foe.  A  torpedo  has  to  have 
a  fairly  deep  covering  of  water,  else  its  course 
will  be  disturbed  by  surface  waves;  and  the 
submarine-chasers  drew  so  little  water  that  a 
torpedo  would  pass  harmlessly  under  them. 
It  was  useless  for  the  U-boat  commander  to 
come  up  and  fight  them  with  his  guns.  They 
would  have  been  upon  him  before  he  could  do 


256      INVENTIONS  OF  THE  GREAT  WAR 

that,  and  their  speed  and  diminutive  size  made 
them  very  difficult  targets  to  hit.  Besides,  he 
dared  not  risk  a  duel  of  shell,  for  he  knew  that 
if  the  precious  inner  hull  of  his  boat  were 
punctured,  he  could  not  seek  refuge  under 
water;  and  if  he  could  not  hide,  he  was  lost. 
The  little  armed  mosquito  craft  swarmed  about 
the  harbor  entrances,  ready  to  dash  at  any  sub- 
marine that  showed  itself.  They  could  travel 
twice  as  fast  as  the  submarine  when  it  was  sub- 
merged and  half  again  as  fast  as  when  it  was 
running  on  the  surface. 

Submarines  had  to  take  to  cover  when  these 
chasers  were  about.  Herr  Kommandant  did 
not  even  dare  to  take  a  look  around  through 
his  periscope,  because  the  streak  of  foam  that 
trailed  in  its  wake  would  betray  him  and  im- 
mediately the  speedy  motor-boats  would  take 
up  the  chase ;  and  they  had  a  disagreeable  way 
of  dropping  bombs  which,  even  if  they  did  not 
sink  the  submarine,  might  produce  such  a  con- 
cussion as  to  spring  its  seams.  His  foes  had 
discovered  one  of  his  most  serious  defects.  He 
was  blind  under-water  and  they  were  making 
the  most  of  this  handicap. 

Groping  along  under-water  by  dead-reckon- 


GETTING  THE  BEST  OF  THE  U-BOAT      257 

ing  was  not  any  too  safe  a  procedure  near  land, 
because  he  was  liable  at  any  moment  to  crash 
into  an  uncharted  rock  or  maybe  into  the  wreck 
of  some  submarine  victim.  He  could  not  cor- 
rect his  bearings  without  coming  to  the  surface, 
and,  in  the  black  depths  of  the  sea,  a  slight  mis- 
calculation might  send  him  to  his  doom.  As 
was  explained  in  the  previous  chapter,  he  had 
to  keep  moving,  because  he  could  not  remain 
suspended  under  water. 

He  was  more  helpless  than  a  ship  sailing 
in  the  densest  of  fogs.  A  ship  can  stop  and 
listen  to  sound-signals,  or  even  to  the  beat- 
ing of  the  surf  on  the  shore,  or  it  can  take 
soundings  to  locate  its  position;  and  yet  it  is 
no  uncommon  occurrence  for  a  ship  to  run 
ashore  in  a  fog.  How  much  easier  it  is  for  a 
submarine  to  lose  its  bearings  when  obliged  to 
travel  by  dead-reckoning,  particularly  in  the 
disconcerting  excitement  of  the  chase!  To 
avoid  the  danger  of  collision  with  surface  ves- 
sels, the  commander  chose  to  run  at  a  depth  of 
sixty-five  feet.  That  wa's  the  upper  limit  of  his 
safety-zone.  A  depth  of -over  two  hundred  feet 
was  his  lower  limit,  because,  as  stated  before, 
the  water-pressure  at  that  depth  would  crush  in 


258      INVENTIONS  OF  THE  GREAT  WAR 

his  hull  or  at  least  start  its  seams.  If  the  bot- 
tom were  smooth  and  sandy,  and  not  too  deep, 
he  could  settle  gently  upon  it  and  wait  for  dark- 
ness, to  make  his  escape. 

But  while  he  lay  on  a  sandy  bottom,  he  was 
still  in  danger.  Trawlers  were  sweeping  the 
bottom  with  nets.  He  might  be  discovered ; 
and  then  if  he  did  not  come  up  and  surrender, 
a  bomb  would  let  in  the  sea  upon  him. 

A    HINT   FROM    NATURE 

While  he  could  not  see  under  water,  his  ad- 
versaries could.  They  had  taken  a  hint  from 
nature.  The  fish-hawk  has  no  difficulty  in  spy- 
ing his  submarine  prey.  Flying  high  above  the 
water,  he  can  see  his  victims  at  a  considerable 
depth,  and  wait  his  chance  to  pounce  upon  an 
unwary  fish  that  comes  too  near  the  surface. 
It  is  said  that  the  British  trained  sea-gulls  to 
hunt  submarines.  Sea-gulls  will  follow  a  ship 
far  out  to  sea  for  the  sake  of  feeding  on  refuse 
that  is  thrown  overboard.  British  submarines 
encouraged  the  birds  to  follow  them,  by  throw- 
ing out  bait  whenever  they  came  to  the  surface. 
Of  course  the  birds  could  see  the  submarine 
even  when  it  was  submerged,  and  if  they  pur- 


GETTING  THE  BEST  OF  THE  U-BOAT      259 

sued  it,  they  were  always  rewarded  with  plenty 
of  food.  The  gulls  drew  no  fine  distinction 
between  Hun  and  Briton,  and  so  it  came  that 
Herr  Kommandant  often  groped  his  way  along 
in  the  dark  sea,  totally  oblivious  of  the  fact  that 
he  was  attended  by  an  escort  of  feathered  folk 
who  kept  the  British  chasers  informed  of  his 
presence. 

In  this  connection  it  is  interesting  to  note 
that  the  British  trained  sea  lions  to  hunt  sub- 
marines. The  animals  were  taught  at  first  to 
swim  to  a  friendly  submarine,  locating  it  by 
the  sound  of  its  propellers.  They  were  always 
rewarded  with  fish.  These  sea  lions  were  muz- 
zled so  that  they  could  not  go  fishing  on  their 
own  account.  Then  they  learned  to  locate 
enemy  submarines  and  pointed  them  out  by 
swimming  directly  toward  them  and  diving 
down  to  them. 

But  there  were  human  eyes,  as  well,  that  spied 
upon  the  U-boat.  Fast  seaplanes  patrolled  the 
waters,  searching  constantly  for  any  trace  of 
submarine.  Its  form  could  be  vaguely  outlined 
to  a  depth  of  from  fifty  to  seventy-five  feet, 
unless  the  sea  were  choppy,  and  once  it  was  dis- 
covered, chasers  or  trawlers  were  signaled  to 


260      INVENTIONS  OF  THE  GREAT  WAR 

destroy  it  with  bombs  or  to  entangle  it  in  nets. 
Often  a  submarine  would  be  discovered  by  a 
leak  in  its  oil-tank  which  would  leave  a  tell- 
tale trail.  Sometimes  when  the  U-boat  itself 
could  not  be  discerned,  there  would  be  slight 
shimmer,  such  as  may  be  seen  above  a  hot  stove, 
caused  by  refraction  of  light  in  its  wake.  This 
was  easily  recognized  by  trained  observers. 

Even  better  aerial  patrols  were  the  small 
dirigibles  known  as  Blimps.  They  are  a  cross 
between  a  balloon  and  an  airplane,  for  they 
have  the  body  and  the  power-plant  of  an  air- 
plane, but  the  planes  are  replaced  by  a  gas- 
bag. Blimps  could  cruise  leisurely  and  search 
the  sea  thoroughly.  They  could  stop  and  hover 
directly  over  a  submarine  and  drop  explosives 
upon  it  with  great  accuracy.  And  so  Herr 
Kommandant  could  take  no  comfort  in  hiding 
under  a  blanket  of  waves  unless  the  blanket  were 
so  thick  as  to  conceal  his  form  completely  from 
the  eyes  overhead.  This  made  it  imperative 
to  leave  the  shallower  waters  near  shore  and 
push  out  into  the  deep  sea,  where  the  small 
chasers  could  not  pursue  him.  But  he  could 
not  shake  off  his  pursuers.  Stream-trawlers 


Courtesy  of  "Scientific  American  " 

Airplane  Stunning  a  U-boat  with  a  Depth-bomb 


GETTING  THE  BEST  OP  THE  U-BOAT      261 

are  built  to  ride  the  heaviest  gales  and  they 
took  up  the  chase  out  into  the  ocean. 

There  was  a  decided  advantage  for  the  U- 
boat  in  moving  out  to  sea.  It  had  a  wider 
field  of  activity  and  could  more  easily  escape 
from  its  pursuers.  But  on  the  other  hand,  its 
prey  also  had  an  advantage.  Out  in  the  open 
ocean  they  were  not  obliged  to  follow  the  usual 
ship  lanes  and  it  was  more  difficult  for  a  sub- 
marine to  intercept  them.  There  it  took  more 
U-boats  to  blockade  a  given  area. 

A   GAME   OF    HIDE-AND-SEEK 

Then,  it  ceased  to  be  quite  so  one-sided  a 
game  when  merchantmen  began  to  carry  guns. 
That  made  it  necessary  for  the  submarine  com- 
mander to  creep  up  on  his  victims  stealthily, 
and  depend  upon  his  torpedoes.  He  had  to 
get  within  a  thousand  yards  of  the  ship  and 
preferably  within  five  hundred  yards,  in  order 
to  be  sure  of  hitting  it.  If  the  ship  could  travel 
faster  than  he  could,  he  had  to  do  this  without 
betraying  his  presence.  But  ship-captains 
soon  learned  that  their  safety  lay  in  zig-zagging. 
When  Herr  Kommandant  reached  the  point 


262      INVENTIONS  OF  THE  GREAT  WAR 

from  which  he  had  planned  to  attack,  he  would 
raise  his  telescopic  periscope  out  of  the  water, 
expecting  to  see  his  victim  within  good  torpedo 
range,  only  to  find  it  sailing  safely  on  another 
tack.  Again,  he  would  have  to  take  observa- 
tions and  make  another  try,  probably  with  no 
better  luck.  It  was  a  game  of  hide-and-seek 
in  which  the  merchant  ship  had  a  good  chance 
of  making  its  escape,  particularly  when  blotches 
of  camouflage  paint  made  it  difficult  for  him  to 
get  the  range,  as  described  in  Chapter  XI. 

Slower  ships  could  be  attacked  without  all 
this  maneuvering,  provided  the  submarine's 
guns  outranged  those  of  the  ship.  And  so  U- 
boats  were  provided  with  larger  and  larger 
guns,  which  made  it  possible  for  them  to  stand 
off  and  pound  the  merchantmen  while  out  of 
reach  of  the  vessel's  guns.  But  ships  found  a 
way  of  hiding  on  the  surface  of  the  sea.  A 
vessel  would  spout  forth  volumes  of  dense  black 
smoke  which  would  obliterate  it  from  view. 
(See  Fig.  19.)  If  the  wind  was  quartering, 
the  ship  would  change  its  course  and  dodge  be- 
hind the  sheltering  pall  of  smoke.  Not  only 
was  the  smoke  produced  on  the  vessel  itself, 
but  smoke-boxes  were  cast  overboard  to  form 


GETTING  THE  BEST  OF  THE  U-BOAT      263 

a  screen  behind  the  vessel.  These  smoke- 
boxes  contained  a  mixture  of  coal-tar  and  phos- 
phorus and  other  chemicals  which  would  pro- 
duce incomplete  combustion.  They  were  ig- 


Courtesy  of  the  Submarine  Defense  Association 

FIG.  19.     How  a  ship  hid  behind  smoke  produced  on  its  own 
stern,  with  different  directions  of  wind 


nited  by  the  rubbing  of  a  phosphorus  compound 
on  a  priming-composition,  and  then  cast  adrift 
to  pour  out  dense  volumes  of  heavy  smoke. 
(See  Fig.  20.)  Behind  this  screen,  the  ship 
could  dodge  and  zig-zag  and  if  her  speed  were 


264      INVENTIONS  OF  THE  GREAT  WAR 

greater  than  that  of  the  submarine,  her  chances 
of  escape  were  very  good. 

Another  annoyance  that  Herr  Kommcmdant 
experienced  was,  when  he  lifted  his  periscopic 


Courtesy  of  the  Submarine  Defense  Association 

FIG.  20.     How  a  ship  hid  behind  a  screen  of  smoke  produeed 
by  throwing  smoke  boxes  overboard 


eye  above  water,  to  find  it  so  smeared  with  a 
sticky  substance  that  he  could  not  see.  His 
foes  had  strewn  the  water  with  tar-oil  that  had 
spread  in  a  thin  film  over  a  surface  miles  in 
extent.  This  blinded  him  at  first,  but  before 


GETTING  THE  BEST  OF  THE  U-BOAT      265 

long  he  was  equipped  with  a  jet  for  washing  off 
the  periscope  glass  and  that  little  annoyance 
was  overcome. 

But  the  craft  most  dreaded  by  the  U-boat 
commander  were  the  destroyers.  These  light, 
high-powered,  heavily  armed  vessels  could 
travel  twice  as  fast  as  he  could  on  the  surface 
and  three  times  as  fast  as  he  could  submerged, 
Shells  were  invented  which  would  not  ricochet 
from  the  surface  of  the  sea,  but  would  plow 
right  through  the  water,  where  they  struck  and 
hit  the  submarine  below  water-level. 

DEATH -DEALING   "ASH    CANS" 

However,  it  was  not  shell-fire  that  he  dreaded, 
but  the  big  "ash  cans"  loaded  with  TNT 
which  were  timed  to  explode  far  under  water, 
and  which  would  crush  his  boat  or  start  its 
seams.  It  was  not  necessary  for  these  bombs 
to  hit  the  U-boat.  When  they  went  off  they 
would  send  out  a  wave  of  pressure  that  would 
crush  the  boat  or  start  its  seams  even  if  it  were 
a  hundred  feet  and  more  from  the  point  of  the 
explosion.  Within  limits,  the  deeper  the  explo- 
sion the  wider  would  its  destructive  area  be. 

The  timing-mechanism  of  some  depth  bombs 


266      INVENTIONS  OF  THE  GREAT  WAR 

consisted  merely  -of  a  float  on  the  end  of  a  cord. 
When  the  bomb  was  thrown  overboard  this 
float  remained  on  the  surface  until  the  cord 
was  pulled  out  to  its  full  length,  when  there 
would  be  a  yank  on  the  firing-trigger  and  the 
charge  would  explode.  In  other  depth  bombs 
there  was  a  valve  operated  by  the  pressure  of 
the  water.  When  the  bomb  sank  to  the  depth 
for  which  the  valve  was  set,  the  pressure  of  the 
water  would  force  the  valve  in,  exploding  a 
cartridge  which  set  off  the  charge.  So  power- 
ful were  these  depth  bombs  that  the  destroyer 
had  to  travel  at  high  speed  to  get  out  of  range 
of  the  explosion. 

Depth  bombs  were  rolled  off  the  stern  of  the 
destroyer  and  also  thrown  out  from  the  sides 
of  the  vessel  by  means  of  mortars.  Some  of 
the  mortars  were  Y-shaped  and  held  a  depth 
bomb  in  each  arm  of  the  Y.  When  a  blank  3- 
inch  shell  was  exploded  at  the  base  of  the  gun, 
both  bombs  would  be  hurled  from  the  ship,  one 
to  port  and  the  other  to  starboard.  In  this  way 
the  destroyer  could  drop  the  bombs  in  a  "  pat- 
tern ' '  of  wide  area.  Herr  Kommandant  gained 
a  wholesome  respect  for  these  terriers  of  the 
sea.  It  was  suicide  to  show  himself  anywhere 


GETTING  THE  BEST  OF  THE  U-BOAT      267 

near  a  destroyer.  In  a  moment  the  speedy  boat 
would  be  upon  him,  sowing  depth  bombs  along 
his  course.  His  chances  of  escaping  through 
this  hail  of  high  explosives  were  remote  in- 
deed. 

The  ships  that  he  was  most  eager  to  destroy 
were  either  too  speedy  for  him  to  catch,  unless 
they  happened  to  come  his  way,  or  else  they 
were  herded  in  large  convoys  protected  by  these 
dreaded  destroyers.  The  convoy  proved  a  most 
baffling  problem  for  Herr  Kommandant.  He 
dared  not  attack  the  convoy  by  daylight.  In  a 
fog  he  might  take  a  chance  at  picking  off  one 
of  the  ships,  but  even  that  was  very  risky.  He 
could  trail  the  convoy  until  dusk  and  then  under 
cover  of  darkness  draw  near  enough  to  dis- 
charge a  torpedo,  but  in  the  daytime  he  must 
keep  his  distance  because  there  were  eyes  in  the 
sky  watching  for  him.  At  the  van  and  rear  of 
the  convoy  there  were  kite  balloons  high  in  the 
sky,  with  observers  constantly  watching  for 
periscopes,  and  for  U-boats  that  might  be  lurk- 
ing under  the  surface. 

As  the  destroyers  gained  in  experience,  the 
difficulties  of  the  U-boat  attack  grew  greater 
and  its  work  grew  more  and  more  perilous. 


268      INVENTIONS  OF  THE  GREAT  WAR 

The  crew  grumbled  and  grew  mutinous.  The 
morale  of  the  men  was  shaken.  We  can 
imagine  the  horror  of  plunging  hurriedly  into 
the  depths  of  the  sea,  and  rushing  along  blindly 
under  the  surface,  dodging  this  way  and  that, 
while  terrific  explosions  of  depth  bombs  stagger 
the  submarine  and  threaten  to  crush  it,  and 
there  is  the  constant  expectation  that  the  next 
explosion  will  tear  the  thin  shell  of  the  U-boat 
and  let  in  the  black  hungry  water.  The  tables 
were  turned.  Now,  if  never  before,  Herr  Kom- 
mandant,  the  hunter,  knew  what  it  felt  like  to 
be  hunted. 

It  takes  an  exceptional  man  to  go  through 
such  a  harrowing  experience  with  unshattered 
nerves.  On  at  least  one  occasion,  a  submarine 
that  was  being  depth-bombed  came  suddenly  to 
the  surface.  The  hatch  flew  open  and  the  crew 
rushed  out,  holding  up  their  hands  and  crying, 
"Kamerad."  The  U-boat  was  uninjured,  but 
the  shock  of  a  depth-bomb  explosion  had  put 
the  electric-lighting  system  out  of  commission, 
and  the  crew,  unnerved  by  the  explosion  and  ter- 
rified by  the  darkness,  had  overpowered  their 
officers  and  brought  the  boat  to  the  surface. 


(C)  Underwood  &  Underwood 

The  False  Hatch  of  a  Mystery  Ship  and 


•JJJ: 


The  same  Hatch  opened  to  disclose  the  3-Inch  Gun  and  Crew 


GETTING  THE  BEST  OF  THE  U-BOAT      269 

EYES   IN   THE   SEA 

There  were  other  craft  that  Herr  Kommm- 
dmt  had  to  look  out  for.  His  were  not  the  only 
submarines  in  the  sea.  His  foes  also  were 
possessed  of  submarines.  They  could  not  see 
under  water  any  better  than  he  could,  but  they 
could  fight  on  the  surface  as  well  as  he,  and 
they  could  creep  up  on  him  even  as  he  crept 
up  on  his  prey.  As  a  French  submarine  com- 
mander puts  it:  "The  U-boats  used  to  enjoy 
the  advantage  of  remaining  themselves  invisible 
while  all  the  surface  and  aerial  craft  which  were 
sent  in  pursuit  of  them  were  boldly  outlined 
against  the  sky  and  visible  to  them.  This  is 
one  of  the  reasons  we  used  submarines  to  am- 
bush U-boats."  Submarines  were  also  used  to 
accompany  the  convoys,  so  that  the  U-boat  com- 
mander had  to  watch  not  only  for  the  eyes 
of  the  ship's  lookouts  and  the  eyes  in  the  kite 
balloons,  but  also  for  the  periscope  eyes  that 
swam  in  the  sea. 

TRAILING   U-BOATS   BY   SOUND 

The  troubles   of  the   submarine-commander 
were  multiplying.     All  over  the  world  inventors 


270      INVENTIONS  OF  THE  GREAT  WAR 

were  plotting  Ms  destruction.  As  long  as  we 
depended  upon  our  eyes  to  ferret  him  out,  the 
sea  was  a  safe  refuge,  provided  he  dived  deep 
enough,  but  when  we  began  to  use  our  ears  as 
well,  he  found  himself  in  a  very  serious  predica- 
ment. Although  light  is  badly  broken  up  in  its 
passage  through  water,  sound-waves  will  travel 
through  water  much  better  than  in  air.  The 
first  listening-devices  used  were  crude  affairs 
and  did  not  amount  to  much,  particularly  when 
the  U-boats  muffled  their  motors  and  engines 
so  that  they  were  virtually  noiseless.  But  the 
French  invented  a  very  sensitive  sound-de- 
tector. It  consisted  of  a  lot  of  tiny  diaphragms 
set  in  a  big  hemisphere.  There  were  two  of 
these  hemispheres,  one  at  each  side  of  the  boat. 
When  sound-waves  struck  these  hemispheres, 
the  diaphragms  would  respond.  At  the  focus 
of  each  hemisphere  there  was  a  megaphone  re- 
ceiver; one  of  these  carried  the  sound  to  the 
operator's  right  ear  and  the  other  to  his  left. 
He  would  turn  a  megaphone  around  until  he 
found  the  diaphragm  that  produced  the  loudest 
sound.  This  gave  him  the  direction  of  the 
sound-wave.  Then  the  boat  would  be  steered 
in  that  direction.  He  knew  that  it  was  aimed 


GETTING  THE  BEST  OF  THE  U-BOAT      271 

properly  when  the  sound  coming  to  his  right  ear 
was  just  as  loud  as  that  which  came  into  his  left 
ear. 

A  still  better  hydrophone  was  developed  by  a 
group  of  American  inventors.  The  details  of 
this  cannot  yet  be  disclosed,  but  we  know  that 
it  was  adopted  at  once  by  our  allies.  A  very 
sensitive  receiver  was  used  which  could  detect 
a  U-boat  miles  away  and  determine  its  direction 
accurately.  Under  ideal  conditions  the  range 
of  the  device  was  from  fifteen  to  twenty-five 
miles,  but  the  average  was  from  three  to  eight 
miles.  If  two  or  more  boats  fitted  with  sound- 
detectors  were  used,  they  could  determine  the 
position  of  the  U-boat  perfectly.  One  draw- 
back was  that  the  vessel  would  have  to  stop 
so  that  the  noise  of  its  own  engines  would  not 
disturb  the  listener,  but  this  was  largely  over- 
come by  trailing  the  detector  a  hundred  feet 
or  more  from  the  stern  of  the  ship.  The  sounds 
were  then  brought  in  by  an  electric  cable  to  the 
listener  in  the  ship. 

These  sound-detectors  were  placed  on  Allied 
submarines  as  well  as  surface  vessels  and  they 
were  actually  tried  out  on  balloons  and  dirigi- 
bles, so  that  they  could  follow  a  U-boat  after  it 


272      INVENTIONS  OF  THE  GREAT  WAR 

had  submerged  too  deeply  to  be  followed  by 
sight. 

Many  U-boats  were  chased  to  their  doom  by 
the   aid   of   the   American   hydrophone.    Fig. 


o  •Listening 
•  *  Depth  Chorye 


Courtesy  of  the  "Scientific  American" 

FIG.  21.     Chart    of    an    actual    pursuit    of    a    U-boat    which 
ended   in   the  destruction  of  the   submarine 


21  illustrates  a  very  dramatic  chase.  The  full 
line  shows  the  course  of  the  U-boat  as  plotted 
out  by  hydrophones  and  the  broken  line  the 
course  of  the  submarine-chasers.  The  dots  rep- 


GETTING  THE  BEST  OF  THE  U-BOAT      273 

resent  patterns  of  depth  bombs  dropped  upon 
the  U-boat.  Try  as  he  would,  the  Herr  Com- 
mandant could  not  shake  off  his  pursuers.  At 
one  time,  as  the  listeners  stopped  to  take  obser- 
vations, they  heard  hammering  in  the  U-boat 
as  if  repairs  were  being  made.  The  motors  of 
the  submarine  would  start  and  stop,  showing 
clearly  that  it  was  disabled.  More  depth  bombs 
were  dropped  and  then  there  was  perfect 
silence,  which  was  soon  broken  by  twenty-five 
revolver-shots.  Evidently  the  crew,  unable  to 
come  to  the  surface,  had  given  up  in  despair 
and  committed  suicide. 

The  Adriatic  Sea  was  an  ideal  place  for  the 
use  of  the  hydrophone.  The  water  there  is  so 
deep  that  submarines  dared  not  rest  on  the 
bottom,  but  had  to  keep  moving,  and  so  they 
could  easily  be  followed.  Across  the  sea,  at  the 
heel  of  the  boot  of  Italy,  a  barrage  of  boats 
was  established.  U-boats  would  come  down  to 
this  barrage  at  night  and,  when  within  two  or 
three  miles  of  the  boats,  dive  and  pass  under 
them.  But  when  hydrophones  were  used  that 
game  proved  very  hazardous.  Our  listeners 
would  hear  them  coming  when  they  were  miles 
away.  Then  they  would  hear  them  shift  from 


274      INVENTIONS  OF  THE  GREAT  WAR 

oil-  to  electric-drive  ^nd  plunge  under  the  sur- 
face. Darkness  was  no  protection  to  the  U- 
boats.  The  sound-detector  worked  just  as  well 
at  night  as  in  the  daytime  and  a  group  of  three 
boats  would  drop  a  pattern  of  bombs  that  would 
send  the  U-boat  to  the  bottom. 

On  one  occasion  after  an  attack  it  was  evident 
that  the  submarine  had  been  seriously  injured. 
Its  motors  were  operating,  but  something  must 
have  gone  wrong  with  its  steering-gear,  or  its 
ballast-chambers  may  have  been  flooded,  be- 
cause it  kept  going  down  -and  soon  the  listeners 
heard  a  crunching  noise  as  it  was  crushed  by 
the  tremendous  pressure  of  the  water. 

And  so  U-boat  warfare  grew  more  and  more 
terrible  for  Herr  Kommandant.  The  depths  of 
the  sea  were  growing  even  more  dangerous  than 
the  surface.  On  every  hand  he  was  losing  out. 
He  had  tried  to  master  the  sea  without  master- 
ing the  surface  of  the  sea.  But  he  can  never 
really  master  who  dares  not  fight  out  in  the 
open.  For  a  time,  the  German  did  prevail,  but 
his  adversaries  were  quick  to  see  his  deficiencies 
and,  by  playing  upon  these,  to  rob  the  terror 
of  the  sea  of  his  powers.  And  as  Herr  Kom- 
mandant looks  back  at  the  time  when  he  stepped 


GETTING  THE  BEST  OF  THE  U-BOAT      275 

into  the  lime-light  as  the  most  brutal  destroyer 
the  world  has  ever  seen,  he  cannot  take  much 
satisfaction  in  reflecting  that  the  sum  total  of 
his  efforts  was  to  spread  hatred  of  Germany 
throughout  the  world,  to  summon  into  the  con- 
flict a  great  nation  whose  armies  turned  the  tide 
of  victory  against  his  soldiers,  and  finally  to 
subject  his  navy,  second  only  to  that  of  Great 
Britain,  to  the  most  humiliating  surrender  the 
world  has  ever  seen. 


CHAPTER  XIV 
" DEVIL'S  EGGS" 

IN  modern  warfare  a  duel  between  fixed  forts 
and  floating  forts  is  almost  certain  to  end 
in  a  draw.  Because  the  former  -are  fixed  they 
make  good  targets,  while  the  war-ship,  being 
able  to  move  about,  can  dodge  the  shell  that  are 
fired  against  it.  On  the  other  hand,  a  fort  on 
land  can  stand  a  great  deal  of  pounding  and 
each  of  its  guns  must  be  put  out  of  action  in- 
dividually, before  it  is  subdued,  while  the  fort 
that  is  afloat  runs  the  risk  of  being  sunk  with 
a  few  well-directed  shots. 

But  fortifications  alone  will  not  protect  a 
harbor  from  a  determined  enemy.  They  can- 
not prevent  hostile  ships  from  creeping  by  them 
under  cover  of  darkness  or  a  heavy  fog.  To 
prevent  this,  the  harbor  must  be  mined,  and  this 
must  be  done  in  such  a  way  that  friendly  ship- 
ping can  be  piloted  through  the  mine-field, 

276 


"DEVIL'S  EGGS"  277 

while  hostile  craft  will  be  sure  to  strike  the 
mines  and  be  destroyed. 

The  mines  may  be  arranged  to  be  fired  by 
electricity  from  shore  stations,  in  which  case 
they  are  anchored  at  such  a  depth  that  ships 
can  sail  over  them  without  touching  them.  If  a 
hostile  vessel  tried  to  dash  into  the  harbor,  the 
touch  of  a  button  on  shore  would  sink  it  when 
it  passed  over  one  of  the  mines.  But  the  suc- 
cess of  electrically  fired  mines  would  depend 
upon  the  "seeing."  In  a  heavy  fog  they  would 
prove  no  protection. 

Another  way  of  using  electric  mines  is  to 
have  telltale  devices  which  a  ship  would  strike 
and  which  would  indicate  to  the  operator  on 
shore  that  a  vessel  was  riding  over  the  mines 
and  would  also  let  him  know  over  which  par- 
ticular mines  it  was  at  the  moment  passing. 
No  friendly  vessel  Wiould  undertake  to  enter 
the  harbor  in  a  fog  or  after  dark  and  the  oper- 
ator would  not  hesitate  to  blow  up  the  invader 
even  if  he  could  not  see  him. 

However,  the  ordinary  method  of  mining  a 
harbor  is  to  lay  fields  of  anchored  mines  across 
the  channels  and  entrances  to  the  harbor — 
sensitive  mines  that  will  blow  up  at  the  slight- 


278      INVENTIONS  OF  THE  GREAT  WAR 

est  touch  of  a  ship's  hull — and  leave  tortuous 
passages  through  the  fields  for  friendly  ship- 
ping. Of  course  pilots  have  to  guide  the  ships 
through  the  passages  and  lest  enemy  spies  learn 
just  where  the  openings  are  the  mine-fields 
must  be  shifted  now  and  then. 

The  mines  are,  therefore,  made  so  that  they 
can  be  -taken  up  by  friendly  mine-sweepers  who 
know  just  how  to  handle  them,  and  planted  else- 
where. These  are  defensive  mines,  but  there 
are  other  mines  that  are  not  intended  to  be 
moved.  They  are  planted  in  front  of  enemy 
harbors  to  block  enemy  shipping  and  they  are 
made  so  sensitive  or  of  such  design  that  they 
will  surely  explode  if  tampered  with. 

THE    MINE   THAT   DOES   ITS   OWN    SOUNDING 

A  favorite  type  of  mine  used  during  the  war 
was  one  which  automatically  adjusted  itself  to 
sink  to  the  desired  depth.  Submerged  mines 
are  more  dangerous  to  the  enemy  because  they 
cannot  be  seen  and  avoided.  They  should  float 
far  enough  under  the  surface  to  remain  hidden 
and  yet  not  so  deep  that  a  shallow-draft  ship 
can  pass  over  them  without  hitting  them.  As 
the  sea  bottom  may  be  very  irregular,  it  is  im- 


"DEVIL'S  EGGS"  279 

possible  to  tell  how  long  the  anchor  cable  should 
be  without  sounding  the  depth  of  the  water  at 
every  point  at  which  a  mine  is  planted.  But 
the  automatic  anchor  takes  care  of  this.  Very 
ingeniously  it  does  its  own  sounding  and  holds 
the  mine  down  to  the  depth  for  which  it  is  set. 
The  mine  cable  is  wound  up  on  a  reel  in  the 
anchor  and  the  mine  is  held  fast  to  the  anchor 
by  a  latch.  The  anchor  is  of  box-shape  or 
cylindrical  form,  with  perforations  in  it.  At 
first  it  sinks  comparatively  slowly,  but  as  it 
fills  with  water  it  goes  down  faster.  Attached 
to  the  anchor  is  a  plummet  or  weight,  connected 
by  a  cord  to  the  latch.  The  length  of  this  cord 
determines  the  depth  at  which  the  mine  will 
float. 

The  operation  of  the  mine  is  shown  in  Fig. 
22.  When  it  is  thrown  overboard  (1)  it  im- 
mediately turns  over  so  that  the  buoyant  mine 
A  floats  on  the  surface  (2).  While  the  anchor 
is  slowly  filling  and  sinking,  the  plummet  B 
runs  out  (3).  If  the  mines  are  to  float  at  a 
depth  of,  say,  ten  feet,  this  cord  must  be  ten 
feet  long.  As  soon  as  it  runs  out  to  its  full 
length  (4)  it  springs  a  latch,  (7,  releasing  the 
mine  A.  Then  the  mine  cable  D  pays  out,  as 


280      INVENTIONS  OF  THE  GREAT  WAR 

the  anchor  E  sinks,  until  the  plummet  B  strikes 
bottom  (5).  As  soon  as  the  plummet  cord 
slackens  a  spring-pressed  pawl  is  released  and 
locks  the  mine-cable  reel,  so  that  as  the  anchor 


Courtesy  of  the  "Scientific  American" 

Fio.  22.     How  the  mine  automatically  adjusts  itself  to  vari- 
ous depths  of  water 


continues  to  sink  it  draws  the  mine  down  with 
it,  until  it  touches  bottom  (6),  and  as  the  anchor 
was  ten  feet  from  the  bottom  when  the  plummet 
touched  bottom  and  locked  the  reel,  the  mine 


" DEVIL'S  EGGS"  281 

must  necessarily  be  dragged  down  to  a  depth 
of  ten  feet  below  the  surface. 

The  mine  itself,  -or  the  "devil's  egg"  as  it 
is  called,  is  usually  a  big  buoyant  sphere  of 
metal  filled  with  TNT  or  some  other  power- 
ful explosive;  and  projecting  from  it  are  a 
number  of  very  fragile  prongs  which  if  broken 
or  even  cracked  will  set  off  the  mine.  There 
is  a  safety-lever  or  pin  that  makes  the  mine 
harmless  when  it  is  being  handled,  and  this 
must  be  withdrawn  just  before  the  mine  is  to 
be  launched.  In  some  mines  the  prongs  are 
little  plungers  that  are  withdrawn  into  the 
mine-shell  and  held  by  a  cement  which  softens 
after  the  mine  is  submerged  and  lets  the 
plungers  spring  out.  When  the  plungers  are 
broken,  water  enters  and,  coming  in  contact 
with  certain  chemicals,  produces  enough  heat  to 
set  off  a  cartridge  which  fires  the  mine. 

PICKING   INFERNAL   MACHINES   OUT    OF    THE   SEA 

The  enemy  mine-fields  were  often  located 
by  seaplanes  and  then  mine-sweepers  had  to 
undertake  the  extremely  hazardous  task  of  rais- 
ing the  mines  or  destroying  them.  If  they 
were  of  the  offensive  type,  it  was  much  better 


282      INVENTIONS  OF  THE  GREAT  WAR 

to  destroy  them.  But  occasionally,  when  con- 
ditions permitted,  mine-sweepers  undertook  to 
raise  the  mines  and  reclaim  them  for  future  use 
against  the  enemy.  The  work  of  seizing  a  mine 
and  making  it  fast  to  the  hoisting-cable  of  the 
mine-sweeper  was  usually  done  from  a  small 
rowboat.  Raising  the  first  mine  was  always 
the  most  perilous  undertaking,  because  no  one 
knew  just  what  type  of  mine  it  was  and  how  to 
handle  it  with  safety,  or  whether  there  was  any 
way  in  which  it  could  be  made  harmless.  There 
were  some  mines,  for  instance,  that  contained 
within  them  a  small  vial  partly  filled  with 
sulphuric  acid.  The  mine  carried  no  prongs, 
but  if  it  were  tilted  more  than  twenty  degrees 
the  acid  would  spill  out  and  blow  up  the  mine. 
Such  a  mine  would  be  exceedingly  difficult  if 
nrot  impossible  to  handle  from  a  boat  that  was 
rocked  about  by  the  waves. 

After  the  first  mine  of  the  field  was  raised 
and  its  safety-mechanism  studied,  the  task  of 
raising  the  rest  was  not  so  dangerous.  A 
water  telescope  was  used  to  locate  the  mine  and 
to  aid  in  hooking  the  hoisting-cable  into  the 
shackle  on  the  mine.  The  hook  was  screwed 
to  the  end  of  a  pole  and  after  the  mine  was 


"DEVIL'S  EGGS"  283 

hooked,  the  pole  was  unscrewed  and  the  cable 
hauled  in,  bringing  up  the  "devil's  egg" 
bristling  with  death.  Care  had  to  be  taken  to 
keep  the  bobbing  boat  from  touching  the  deli- 
cate prongs  until  the  safety-device  could  be 
set. 

However,  this  painstaking  and  careful 
method  of  raising  mines  was  not  often  em- 
ployed. Shallow-draft  mine-sweepers  would 
run  over  the  mine-field,  dragging  a  cable  be- 
tween them.  The  cable  would  be  kept  down  by 
means  of  hydrovanes  or  "water  kites "  deep 
enough  to  foul  the  anchor  cables  of  the  mines. 
The  "water  kites "  were  V-shaped  structures 
that  were  connected  to  the  cable  in  such  a  way 
that  they  would  nose  down  as  they  were 
dragged  through  the  water  and  carry  the  cable 
under.  The  action  is  just  the  reverse  of  a  kite, 
which  is  set  to  nose  up  into  the  wind  and  carry 
the  kite  up  when  it  is  dragged  through  the  air. 
By  means  of  the  cable  the  anchor  chain  of  the 
mine  was  caught  and  then  the  mine  with  its 
anchor  was  dragged  up.  If  the  mine  broke 
loose  from  its  anchor  it  could  be  exploded  with 
a  rifle-shot  if  it  did  not  automatically  explode 
on  fouling  the  cable. 


284      INVENTIONS  OF  THE  GREAT  WAR 

FLOATING    MINES 

When  England  entered  the  war  she  mined  her 
harbors  because,  although  she  had  the  mastery 
of  the  sea,  she  had  to  guard  against  raids  of 
enemy  ships  carried  out  in  foggy  and  dark 
weather.  But  the  mines  were  no  protection 
against  submarines.  They  would  creep  along 
the  bottom  under  the  mines.  Then  cable  nets 
were  stretched  across  the  harbor  channels  to 
bar  the  submarines,  but  the  U-boats  were 
fitted  with  cutters  which  would  tear  through 
the  nets,  and  it  became  necessary  to  use  mines 
set  at  lower  depths  so  that  the  submarines  could 
not  pass  under  them;  and  nets  were  furnished 
with  bombs  which  would  explode  when  fouled 
by  submarines.  In  fact,  mines  were  set  adrift 
with  nets  stretched  between  them,  to  trap  sub- 
marines. Floating  mines  were  also  used  by  the 
Germans  for  the  destruction  of  surface  vessels 
and  these  were  usually  set  adrift  in  pairs,  with 
a  long  cable  connecting  them,  so  that  if  a  vessel 
ran  into  the  cable  the  mines  would  be  dragged 
in  against  its  hull  and  blow  it  up. 

The  laws  of  war  require  that  floating  mines  be 


' 'DEVIL'S  EGGS"  285 

of  such  a  design  that  they  will  become  inopera- 
tive in  a  few  hours;  otherwise  they  might  drift 
about  for  weeks  or  months  or  years  and  be  a 
constant  menace  to  shipping.  Sometimes 
anchored  mines  break  away  from  their  moor- 
ings and  are  carried  around  by  ocean  currents 
or  are  blown  about  by  the  winds.  A  year 
after  the  Eusso-Japanese  War  a  ship  was 
blown  up  by  striking  a  mine  that  had  been  torn 
from  its  anchorage  and  had  drifted  far  from 
the  field  in  which  it  was  planted.  No  doubt 
there  are  hundreds  of  mines  afloat  in  the 
Atlantic  Ocean  which  for  many  years  to  come 
will  hold  out  the  threat  of  sudden  destruction 
to  ocean  vessels ;  for  the  Germans  knew  no  laws 
of  war  and  had  no  scruples  against  setting 
adrift  mines  that  would  remain  alive  until  they 
were  eaten  up  with  rust. 

The  chart  on  the  next  page  shows  the  course 
of  ocean  currents  in  the  North  Atlantic  as 
plotted  out  by  the  Prince  of  Monaco,  from  which 
it  may  be  seen  that  German  mines  will  prob- 
ably make  a  complete  circuit  of  the  North 
Atlantic,  drifting  down  the  western  coast  of 
Europe,  across  the  Atlantic,  around  the  Azores, 


286      INVENTIONS  OF  THE  GREAT  WAR 

and  into  the  Gulf  Stream,  which  will  carry  them 
back  to  the  North  Sea,  only  to  start  all  over. 
(See  Fig.  23.)  Some  of  them  will  run  up  into 
the  Arctic  Ocean,  where  they  will  be  blown  up 
by  striking  icebergs  and  many  will  be  trapped 
in  the  mass  of  floating 
seaweed  in  the  Sargasso 
Sea.  But  many  years 
will  pass  before  all  dan- 
ger of  mines  will  be  re- 


Courtosy  of  the  "Scientific  American" 

Flo.  23.     Ocean  currents  of  the  North  Atlantic  showing  the 
probable  path  of  drifting  mines 


moved.  In  the  meantime,  the  war  has  left  a 
tremendous  amount  of  work  to  be  done  in  rais- 
ing anchored  mines  and  destroying  them. 


" DEVIL'S  EGGS"  287 

EGG-LAYING  SUBMARINES 

Early  in  the  war  the  British  were  astonished 
to  find  enemy  mine-fields  in  their  own  waters, 
far  from  any  German  ports.  They  could  not 
have  been  planted  by  surface  mine-layers,  un- 
less these  had  managed  to  creep  up  disguised 
as  peaceful  trawlers.  This  seemed  hardly 
likely,  because  these  fields  appeared  in  places 
that  were  well  guarded.  Then  it  was  dis- 
covered that  German  U-boats  were  doing  this 
work.  Special  mine-laying  U-boats  had  been 
built  and  one  of  them  was  captured  with  its 
cargo  of  "devil's  eggs." 

A  sectional  view  of  the  mine-laying  U-boat 
is  shown  opposite  page  272.  In  the  after  part 
of  the  boat  were  mine-chutes  in  each  of  which 
three  mines  were  stored.  A  mine-laying  sub- 
marine would  carry  about  a  score  of  mines. 
These  could  be  released  one  at  a  time.  The 
mine  with  its  anchor  would  drop  to  the  bottom. 
As  soon  as  it  struck,  anchor-arms  would  be 
tripped  and  spread  out  to  catch  in  the  sand  or 
mud,  while  the  mine  cable  would  be  released 
and  the  mine  would  rise  as  far  as  the  cable 
would  allow  it.  The  U-boat  commander  would 


288      INVENTIONS  OF  THE  GREAT  WAR 

have  to  know  the  depth  of  water  in  which 
the  mines  were  to  be  laid  and  adjust  the  cables 
to  this  depth  in  advance.  This  could  not  be 
done  while  the  U-boat  was  submerged  With 
the  mines  all  set  for  the  depth  at  a  certain  spot, 
the  U-boat  commander  had  to  find  that  very 
spot  to  lay  his  "eggs,"  otherwise  they  would 
either  lie  too  deep  to  do  any  harm  to  shipping, 
or  else  they  would  reach  up  to  the  surface, 
where  they  might  be  discovered  by  the  Allied 
patrols.  As  he  had  to  do  his  navigating  blindly, 
by  dead-reckoning,  it  was  very  difficult  for  him 
to  locate  his  mine-fields  properly. 

But  the  Germans  did  not  have  a  monopoly 
on  submarine  mine-laying.  The  British  also 
laid  mines  by  submarine  within  German  har- 
bors and  channels,  right  under  the  guns  of 
Heligoland,  and  many  a  U-boat  was  destroyed 
by  such  mines  within  its  home  waters. 

PABAVA9E8 

On  the  other  hand,  the  Allies  had  a  way  of 
sailing  right  through  fields  of  enemy  mines 
with  little  danger.  Our  ships  were  equipped 
with  "paravanes"  which  are  something  like 
the  i4 water  kites*1  used  by  mine-sweepers,  and 


\!ui< 


" DEVIL'S  EGGS"  289 

they  are  still  used  in  the  waters  of  the  war  zone. 
Paravanes  are  steel  floats  with  torpedo-shaped 
bodies  and  a  horizontal  plane  near  the  for- 
ward end.  At  the  tail  of  the  paravane,  there 
are  horizontal  and  vertical  rudders  which  can  be 
set  to  make  the  device  run  out  from  the  side  of 
the  vessel  that  is  towing  it,  and  at  the  desired 
depth  below  the  surface.  Two  paravanes  are 
used,  one  at  each  side  of  the  ship,  and  the  tow- 
ing-cables  lead  from  the  bow  of  the  vessel. 
Thus  there  are  two  taut  cables  that  run  out 
from  the  ship  in  the  form  of  a  V  and  at  such  a 
depth  that  they  will  foul  the  mooring-cable  of 
any  mine  that  might  be  encountered.  The  mine 
cable  slides  along  the  paravane  cable  and  in 
this  way  is  carried  clear  of  the  ship's  hull. 
When  it  reaches  the  paravane  it  is  caught  in  a 
sharp-toothed  jaw  which  cuts  the  mine  cable  and 
lets  the  mine  bob  up  to  the  surface.  The  mine 
is  then  exploded  by  rifle  or  machine-gun  lire. 
In  some  forms  of  paravane  there  is  a  hinged 
jaw  which  is  operated  from  the  ship  to  shear  the 
cable.  The  jaw  is  repeatedly  opened  and 
closed  by  a  line  that  runs  to  a  winch  on  the  ship. 
This  winch  winds  up  the  line  until  it  is  taut 
and  then  the  line  is  permitted  to  slip,  letting 


290      INVENTIONS  OF  THE  GREAT  WAR 

the  jaw  open,  only  to  close  again  as  the  winch 
keeps  on  turning  and  winding  up  the  line. 

Guarded  by  steel  sharks  on  each  side,  their 
jaws  constantly  working,  a  ship  can  plow  right 
through  a  field  of  anchored  mines  with  little 
danger.  To  be  sure,  the  bow  might  chance  to 
hit  a  mine,  when,  of  course,  there  would  be  an 
explosion ;  but  the  ship  could  stand  damage  here 
better  than  anywhere  else  and  unless  the  bow 
actually  hit  the  mine,  one  or  other  of  the  para- 
vanes would  take  care  of  it  and  keep  it  from 
being  dragged  in  against  the  hull  of  the  vessel. 

PENNING    IN    THE    U-BOATS 

According  to  German  testimony,  mines  were 
responsible  for  the  failure  of  the  U-boat.  How- 
ever, it  was  not  merely  the  scattered  mine- 
fields sown  in  German  waters  that  brought  the 
U-boat  to  terms,  but  an  enormous  mine-field 
stretching  across  the  North  Sea  from  the  Orkney 
Islands  to  the  coast  of  Norway.  Early  in  the 
war,  U-boats  had  been  prevented  from  entering 
the  English  Channel  by  nets  and  mines  stretched 
across  the  Straits  of  Dover.  As  the  submarine 

V 

menace  grew,  it  was  urged  that  a  similar  net 
be  stretched  across  the  North  Sea  to  pen  the 


"DEVIL'S  EGGS"  291 

U-boats  in.  But  it  seemed  like  a  stupendous 
task.  The  distance  across  at  the  narrowest 
point  is  nearly  two  hundred  and  fifty  miles. 
It  would  not  have  been  necessary  to  have  the 
net  come  to  the  surface.  It  could  just  as  well 
have  been  anchored  so  that  its  upper  edge 
would  be  covered  with  thirty  feet  of  water. 
Surface  vessels  could  then  have  sailed  over  it 
without  trouble  and  submarines  could  not  have 
passed  over  it  without  showing  themselves  to 
patrolling  destroyers.  It  would  not  have  been 
necessary  to  carry  the  net  to  the  bottom  of  the 
sea.  A  belt  of  netting  a  hundred  and  fifty  feet 
wide  would  have  made  an  effective  bar  to  the 
passage  of  U-boats.  As  U-boats  might  cut  their 
way  through  the  net,  it  was  proposed  to  mount 
bombs  or  mines  on  them  which  would  explode  on 
contact  and  destroy  any  submarine  that  tried  to 
pass.  However,  laying  a  net  two  hundred  feet 
long  even  when  it  is  laid  in  sections,  is  no  small 
job,  but  when  the  net  is  loaded  with  contact 
mines,  the  difficulty  of  the  work  may  be  well 
imagined. 

And  yet  had  it  been  thought  that  the  net  would 
be  a  success  it  would  have  been  laid  anyhow, 
but  it  was  argued  that  seaweed  would  clog  the 


292      INVENTIONS  OF  THE  GREAT  WAR 

meshes  of  the  net  and  ocean  currents  would  tear 
gaps  in  it.  Even  if  it  had  not  been  torn  away, 
the  tidal  currents  would  have  swept  it  down  and 
borne  it  under  so  far  that  U-boats  could  have 
passed  over  it  in  safety  without  coming  to  the 
surface. 

A   WALL   OF   MINES 

When  America  entered  the  war,  we  were  very 
insistent  that  something  must  be  done  to  block 
the  North  Sea,  and  we  proposed  that  a  barrage 
of  anchored  mines  be  stretched  across  the  sea 
and  that  these  mines  be  set  at  different  levels 
so  as  to  make  a  "wall"  that  submarines  could 
not  dive  under.  This  would  do  away  with  all 
the  drawbacks  of  a  net.  Ocean  currents  and 
masses  of  seaweed  could  not  affect  individual 
mines  as  they  would  a  net.  Furthermore,  an 
American  inventor  had  devised  a  new  type  of 
mine  which  was  peculiarly  adapted  to  the  pro- 
posed mine  barrage.  It  had  a  firing-mechan- 
ism that  was  very  sensitive  and  the  mine 
had  twice  the  reach  of  any  other. 

At  length  the  British  mine-laying  forces  were 
prevailed  upon  to  join  with  us  in  laying  this 
enormous  mine.  It  was  one  of  the  biggest  and 


"DEVIL'S  EGGS"  293 

most  successful  undertakings  of  the  war.  It 
was  to  be  two  hundred  and  thirty  miles  long 
and  twelve  miles  wide  on  the  average,  reaching 
from  the  rocky  shores  of  the  Orkney  Islands 
to  Norway.  There  was  plenty  of  deep  water 
close  to  the  coast  of  Norway  and  it  was  against 
international  law  to  lay  mines  within  three  miles 
of  the  shores  of  a  neutral  nation,  so  that  the  U- 
boats  might  have  had  a  clear  passage  around  the 
end  of  the  barrage.  But  as  it  was  also  against 
the  law  for  the  U-boats  to  sail  through  neutral 
waters,  Norway  laid  a  mine-field  off  its  coast 
to  enforce  neutrality,  and  this  was  to  join  with 
that  which  the  British  and  we  were  to  lay. 
Most  of  the  mine-laying  was  to  be  done  by  the 
United  States  and  we  were  to  furnish  the  mines. 
The  order  to  proceed  with  the  work  was  given 
in  October,  1917,  and  it  was  a  big  order.  A 
hundred  thousand  mines  were  to  be  made  and  to 
preserve  secrecy,  as  well  as  to  hurry  the  work 
as  much  as  possible,  it  was  divided  among  five 
hundred  contractors  and  subcontractors.  The 
parts  were  put  together  in  one  plant  and  then 
sent  to  another,  where  each  mine  was  filled  with 
three  hundred  pounds  of  molten  TNT.  To 
carry  them  across  the  ocean  small  steamers 


294      INVENTIONS  OF  THE  GREAT  WAR 

were  used,  so  that  if  one  should  be  blown  up 
by  a  submarine  the  loss  of  mines  would  not  be 
very  great.  There  were  twenty-four  of  these 
steamers,  each  carrying  from  twelve  hundred  to 
eighteen  hundred  mines  and  only  one  of  them 
was  destroyed  by  a  submarine.  The  steamers 
delivered  their  loads  on  the  west  coast  of  Scot- 
land and  the  mines  were  taken  across  to  the 
east  coast  by  rail  and  motor  canal-boats.  Here 
the  mines  were  finally  assembled,  ready  for 
planting.  Seventy  thousand  mines  were 
planted,  four  fifths  of  them  by  American  mine- 
layers and  the  rest  by  the  British. 

MINE   RAILROADS   ON   SHIPS 

To  handle  the  mines  the  ships  were  specially 
fitted  with  miniature  railroads  for  transporting 
the  mines  to  the  launching-point,  so  that  they 
could  be  dropped  at  regular  intervals  without 
interruption.  Each  anchor  mine  was  provided 
with  flanged  wheels  that  ran  on  rails.  The 
mines  were  carried  on  three  decks  and  each 
deck  was  covered  with  a  network  of  rails, 
switches,  and  turn-tables,  while  elevators  were 
provided  to  carry  the  mines  from  one  deck  to 
another.  The  mines,  like  miniature  railroad 


"DEVIL'S  EGGS"  295 

cars,  were  coupled  up  in  trains  of  thirty  or  forty 
and  as  each  mine  weighed  fourteen  hundred 
pounds,  steam  winches  had  to  be  used  to  haul 
them.  At  the  launching-point  the  tracks  ran  out 
over  the  stern  of  the  boat  and  here  a  trap  was 
provided  which  would  hold  only  one  mine  at  a 
time.  By  the  pulling  of  a  lever  the  jaws  of  the 
trap  would  open  and  the  mine  would  slide  off  the 
rails  and  plunge  into  the  sea. 

The  mines  were  dropped  every  three  hundred 
feet  in  lines  five  hundred  feet  apart,  as  it  was 
unsafe  for  the  mine-layers  to  steam  any  closer 
to  one  another  than  that.  The  mines  were  of 
the  type  shown  in  Fig.  22  and  automatically 
adjusted  themselves  to  various  depths.  The 
depth  of  the  water  ran  down  to  twelve  hundred 
feet  near  the  Norwegian  coast.  Never  before 
had  mines  been  planted  at  anywhere  near  that 
depth. 

It  was  dangerous  work,  because  the  enemy 
knew  where  the  mines  were  being  planted,  as 
neutral  shipping  had  to  be  warned  months  in  ad- 
vance. The  mine-layers  were  in  constant 
danger  of  submarine  attack,  although  they  were 
convoyed  by  destroyers  to  take  care  of  the 
U-boats.  There  was-  even  danger  of  a  surface 


296      INVENTIONS  OF  THE  GREAT  WAR 

attack  and  so  battle-cruisers  were  assigned  the 
job  of  guarding  the  mine-layers.  The  mine- 
layers steamed  in  line  abreast,  and  had  one  of 
them  been  blown  up,  the  shock  would  probably 
have  been  enough  to  blow  up  the  others  as  well. 
Enemy  mines  were  sown  in  the  path  of  the 
mine-layers,  so  the  latter  had  to  be  preceded  by 
mine-sweepers.  Navigation  buoys  had  to  be 
planted  at  the  ends  of  the  lines  of  mines  and  the 
enemy  had  a  habit  of  planting  mines  near  the 
buoys  or  of  moving  the  buoys  whenever  he  had 
a  chance.  But  despite  all  risks  the  work  was 
carried  through. 

The  barrier  was  not  an  impassable  one.  With 
the  mines  three  hundred  feet  apart,  a  submarine 
might  get  through,  even  though  the  field  was 
twenty-five  miles  broad,  but  the  hazards  were 
serious.  Before  the  first  lines  of  mines  had  been 
extended  half-way  across,  its  value  was  demon- 
strated by  the  destruction  of  several  U-boats, 
and  as  the  safety-lane  was  narrowed  down  the 
losses  increased.  It  is  said  that  altogether 
twenty-three  German  submarines  met  their 
doom  in  the  great  mine  barrage.  U-boat  com- 
manders balked  at  running  through  it,  and 
U-boat  warfare  virtually  came  to  a  standstill. 


" DEVIL'S  EGGS"  297 

According  to  Captain  Bartenbach,  commander 
of  submarine  bases  in  Flanders,  three  U-boats 
were  sunk  by  anchored  mines  for  every  one  that 
was  destroyed  by  a  depth  bomb. 


CHAPTEE  XV 

SURFACE  BOATS 

THE   war   on   the   submarine   was   fought 
mainly  from  the  surface  of  the  sea  and 
from  the  air  above  the  sea,  and  naturally  it 
resulted   in  many   interesting  naval   develop- 
ments. 

As  described  in  Chapter  XIII,  the  first  offen- 
sive measure  against  the  U-boat  was  the  build- 
ing of  swarms  of  speedy  motor-boats  which 
drove  the  invaders  away  from  harbors  and  into 
the  open  sea.  To  follow  the  U-boats  out  into 
rough  water  larger  submarine-chasers  were 
built,  but  even  they  could  not  cope  with  the 
enemy  far  from  the  harbors. 

MOTOR   TORPEDO-BOATS 

The  Italians  made  excellent  use  of  speedy 
motor-boats  in  the  protected  waters  of  the  Adri- 
atic Sea.  One  type  of  motor-boat  was  equipped 

298 


SURFACE  BOATS  299 

with  two  torpedo-tubes  in  the  bow.  Small  14- 
inch  torpedoes  were  used,  but  as  each  torpedo 
carried  two  hundred  pounds  of  high  explosive, 
the  motor-boat  was  a  formidable  vessel  if  it 
crept  in  close  enough  to  discharge  one  of  these 
missiles  at  its  foe. 

On  one  occasion,  a  patrol  of  these  little  boats 
sighted  a  couple  of  Austrian  dreadnoughts 
headed  down  the  coast,  surrounded  by  a  screen 
of  ten  destroyers.  Favored  by  the  mist,  two  of 
the  motor-boats  crept  through  the  screen  of  de- 
stroyers, and  torpedoed  the  battle-ships.  Then 
they  made  good  their  escape.  A  destroyer  that 
pursued  one  of  the  boats  decided  that  the  game 
was  not  worth  while  when  it  was  suddenly 
shaken  up  by  the  explosion  of  a  depth  bomb 
dropped  from  the  motor-boat. 

THE    SEA   TANK 

The  Italians  showed  a  great  deal  of  naval  in- 
itiative. They  were  forever  trying  to  trap  the 
Austrian  fleet  or  to  invade  its  harbors.  Like 
all  other  naval  powers,  the  Austrians  protected 
their  harbors  with  nets  and  mines.  It  was  im- 
possible for  submarines  to  make  an  entrance  and 
the  ports  were  too  well  fortified  to  permit  an 


300      INVENTIONS  OF  THE  GREAT  WAB 

open  attack  on  the  surface.  Nevertheless,  the 
Italians  did  break  through  the  harbor  defenses 
on  one  or  two  occasions  and  sank  Austrian  war- 
vessels.  Again  it  was  with  a  small  boat  that 
they  did  the  trick. 

The  nets  which  the  Austrians  stretched  across 
their  harbor  entrance  were  supported  on  wooden 
booms  or  logs  which  served  as  floats.  These 
booms  offered  an  effective  bar  to  small  boats 
which  might  attempt  to  enter  the  harbor  under 
cover  of  darkness.  But  the  Italians  found  a 
way  to  overcome  this  obstruction.  They  built 
a  flat-l>ottome<l  motor-boat  which  drew  very 
little  water.  Running  under  the  boat  were  two 
endless  chains,  like  the  treads  (if  a  tank.  In 
fact,  the  boat  came  to  IK*  known  as  a  "sea  tank." 
The  chains  were  motor-driven  ami  had  spiked 
sprockets,  so  that  when  a  boom  was  encountered 
they  would  bite  into  the  wood  and  pull  the  boat 
up  over  the  log,  or  maybe  they  would  drag  the 
log  down  under  the  boat.  At  any  rate,  with  this 
arrangement  it  was  not  very  difficult  to  pass  the 
boom  and  enter  the  harbor.  At  the  rear  the 
chains  were  carried  back  far  enough  to  prevent 
the  propeller  from  striking  when  the  boat  had 
passed  over  the  log. 


SURFACE  BOATS  301 

THE   AWKWARD   "  EAGLES " 

A  curious  boat  that  we  undertook  to  furnish 
during^he  war  was  a  cross  between  a  destroyer 
and  a  submarine-chaser.  After  the  submarine 
had  been  driven  out  to  sea  its  greatest  foe  was 
undoubtedly  the  destroyer,  and  frantic  efforts 
were  made  to  turn  out  as  many  destroyers  as 
possible.  But  it  takes  time  to  build  destroyers 
and  so  a  new  type  of  boat  was  designed,  to  be 
turned  out  quickly  in  Inrge  numbers.  A  hun- 
dred and  ten  "Eagles"  (as  these  boats  are 
called)  were  ordered,  but  the  armistice  was 
signed  before  any  of  them  were  put  into  service ; 
and  it  is  just  as  well  that  such  was  the  case,  for 
in  their  construction  everything  was  sacrificed 
to  speed  of  production.  As  a  consequence  they 
are  very  ugly  boats,  with  none  of  the  fine  lines 
of  a  destroyer,  and  they  roll  badly,  even  when 
the  sea  is  comparatively  peaceful.  They  are 
five-hundred-ton  boats  designed  to  make  eight- 
een knots,  which  would  not  have  been  fast 
enough  to  cope  with  U-boats,  because  the  latter 
could  make  as  high  a  speed  as  that  themselves, 
when  traveling  on  the  surface,  and  the  two 
4-inch  guns  of  the  Eagles  would  have  been  far 


302      INVENTIONS  OP  THE  GREAT  WAR 

outranged  by  the  5.9-inch  guns  of  the  larger 
U-boats. 


SEAPLANE   TOWING-BAKGES 

When  the  war  on  the  U-boat  was  earned  up 
into  the  sky,  many  new  naval  problems  cropped 
up,  particularly  when  German  submarines 
chose  to  work  far  out  at  sea.  Big  seaplanes 
were  used,  but  they  consumed  a  great  deal  of 
fuel  in  flying  out  and  back,  cutting  down  by  just 
so  much  their  flying-radius  at  the  scene  of  activi- 
ties. A  special  towing-barge  was  used.  These 
barges  had  trimming-tanks  aft,  which  could  be 
flooded  so  that  the  stern  of  the  barge  would  sub- 
merge. A  cradle  was  mounted  to  run  on  a  pair 
of  rails  on  the  barge.  The  body  of  the  seaplane 
was  lashed  to  this  cradle  and  then  drawn  up  on 
the  barge  by  means  of  a  windlass.  This  done, 
the  water  was  blown  out  of  the  trimming- tanks 
by  means  of  compressed  air  and  the  barge  was 
brought  up  to  an  even  keel.  The  barge  with 
its  load  was  now  ready  to  be  towed  by  a  de- 
stroyer or  other  fast  boat  to  the  scene  of  opera- 
tions. There  water  was  again  let  into  the 
trimming-tanks  and  the  seaplane  was  let  back 


SURFACE  BOATS  303 

into  the  water.  From  the  water  the  seaplane 
arose  into  the  air  in  the  usual  way. 

Unfortunately,  when  the  sea  is  at  all  rough 
it  is  exceedingly  difficult  for  a  seaplane  to  take 
wing,  ^Irticularly  a  large  seaplane.  A  better 
starting-platform  than  the  sea  had  to  be  fur- 
nished. At  first  some  seaplanes  were  furnished 
with  wheels,  so  that  they  could  be  launched  from 
platforms  on  large  ships;  and  then,  to  increase 
the  flying-radius,  seaplanes  were  discarded  in 
favor  of  airplanes.  Once  these  machines  were 
launched,  there  was  no  way  for  them  to  get 
back  to  the  ship.  They  had  to  get  back  to  land 
before  their  fuel  was  exhausted. 

On  the  large  war-vessels  *a  starting-platform 
was  built  on  a  pair  of  long  guns.  Then  the 
war-ship  would  head  into  the  wind  and  the  com- 
bined travel  of  the  ship  and  of  the  airplane 
along  the  platform  gave  speed  -enough  to  raise 
the  plane  off  the  platform  before  it  had  run  the 
full  length  of  the  guns.  But  as  long  as  aviators 
had  no  haven  until  they  got  back  to  land,  there 
were  many  casualties.  Eager  to  continue  their 
patrol  as  long  as  possible,  they  would  some- 
times linger  too  long  before  heading  for  home 


304      INVENTIONS  OF  THE  GREAT  WAR 

and  then  they  would  not  have  enough  fuel  left 
to  reach  land.  Many  an  aviator  was  lost  in  this 
way,  and  finally  mother-ships  for  airplanes  had 
to  be  built. 

% 
THE  "HUSH  SHIPS" 

The  British  Navy  had  constructed  a  number  of 
very  fast  cruisers  to  deal  with  any  raiders  the 
Germans  might  send  out.  These  cruisers  were 
light  vessels  capable  of  such  high  speeds  that 
they  could  even  overtake  a  destroyer.  They 
were  840  feet  long  and  their  turbines  developed 
90,000  horse-power.  The  construction  of  these 
vessels  was  for  a  long  time  kept  a  profound 
secret  and  it  was  not  until  the  German  fleet 
surrendered  that  photographs  of  them  were  al- 
lowed to  be  published.  Because  of  this  secrecy 
the  boats  were  popularly  known  as  "  hush- 
ships.  "  They  were  not  armored;  it  was  not 
necessary  to  load  them  down  with  armor  plate, 
because  their  protection  lay  in  speed  and  they 
were  designed  to  fight  at  very  long  range.  In 
fact,  they  were  to  carry  guns  that  would  out- 
range those  of  the  most  powerful  dreadnoughts. 
Our  largest  naval  guns  are  of  16-inch  caliber, 
but  the  "hush  ships M  were  each  to  carry  two 


SURFACE  BOATS  305 

18-inch  guns.  The  guns  were  monsters  weigh- 
ing 150  tons  each  and  they  fired  a  shell  18  inches 
in  diameter  and  7  feet  long  to  a  distance  of  30 
miles  when  elevated  to  an  angle  of  45  degrees. 
The  weight  of  the  shell  was  3600  pounds  and  it 
carried  500  pounds  of  high  explosive  or  more 
than  is  carried  in  the  largest  torpedoes. 

At  the  32-mile  range  the  shell  would  pass 
through  12  inches  of  face-hardened  armor  and 
at  half  that  range  it  would  pass  through  armor 
18  inches  thick,  and  there  is  no  armor  afloat  any 
heavier  than  this. 

MOTHER-BOATS   FOB   AIRPLANES 

Armed  with  such  powerful  guns  as  these,  the 
"hush  ships "  would  have  been  very  formidable 
indeed ;  but  when  the  guns  were  mounted  on  one 
of  the  cruisers,  the  Furious,  they  were  found 
too  powerful  for  the  vessel.  It  was  evident  that 
the  monsters  would  very  -seriously  rack  their 
own  ship.  So  the  guns  were  taken  off  the 
cruiser  and  it  was  turned  into  a  mother-ship 
for  airplanes.  A  broad,  unobstructed  deck  was 
built  on  the  ship  which  provided  a  runway  from 
which  airplanes  could  be  launched,  and  this  run- 
way was  actually  broad  enough  to  permit  air- 


306      INVENTIONS  OF  THE  GREAT  WAR 

planes  to  land  upon  it.  Under  the  runway  were 
the  hangars  in  which  the  airplanes  were  housed. 
Other  "hush  ships'*  were  also  converted  into 
airplane  mother-boats  and  there  were  special 
boats  built  for  this  very  purpose,  although  they 
were  not  .able  to  make  the  speed  of  the  "hush 
ships. "  One  of  these  special  boats  had  funnels 
that  turned  horizontally  to  carry  off  the  furnace 
smoke  over  the  stern  and  leave  a  perfectly  clear 
flying-deck,  330  feet  long. 

TOBPHDO-PBOOF   MONSTERS 

As  for  the  18-inch  guns,  they  were  put  to  an- 
other use.  Early  in  the  war  the  British  had 
need  for  powerful  shallow-draft  vessels  which 
could  operate  off  the  Flanders  coast  and  attack 
the  coast  fortifications  that  were  being  built  by 
the  Germans.  The  ships  that  were  built  to 
meet  this  demand  were  known  as  monitors,  be- 
cause like  the  famous  "  monitor "  of  our  Civil 
War  they  carried  a  single  turret.  These  moni- 
tors were  very  broad  for  their  length  and  were 
very  slow.  At  best  they  could  make  only  seven 
knots  and  in  heavy  weather  they  could  not  make 
more  than  two  or  three  knots. 

To  be  made  proof  against  torpedoes  these 


SURFACE  BOATS  307 

boats  were  formed  with  "blisters"  or  hollow 
rounded  swells  in  the  hull  at  each  side  which 
extended  out  to  a  distance  of  twelve  to  fifteen 
feet.  The  blisters  were  subdivided  into  com- 
partments, so  that  if  a  torpedo  struck  the  ship 
it  would  explode  against  a  blister  at  a  consider- 
able distance  from  the  real  hull  of  the  ship  and 
the  force  of  the  explosion  would  be  expended 
in  the  compartments.  The  blisters  were  the 
salvation  of  the  monitors.  Often  were  the  boats 
struck  by  torpedoes  without  being  sunk. 

Unfortunately,  this  form  of  protection  could 
not  be  applied  to  ordinary  vessels,  because  it 
would  have  interfered  seriously  with  navigation. 
The  blisters  made  the  monitors  very  difficult 
to  steer  and  hampered  the  progress  of  a  ship, 
particularly  in  a  seaway. 

With  ships  such  as  these  the  British  bom- 
barded Zeebrugge  from  a  distance  of  twenty  to 
twenty-five  miles.  Of  course,  the  range  had  to 
be  plotted  out  mathematically,  as  the  target  was 
far  beyond  the  horizon  of  the  ship,  and  the 
firing  had  to  be  directed  by  spotters  in  air- 
planes. 

At  first  guns  from  antiquated  battle-ships 
were  used  in  the  monitors;  then  larger  guns 


308      INVENTIONS  OF  THE  GREAT  WAR 

were  used,  until  finally  two  of  the  monitors  in- 
herited the  18-inch  guns  of  the  Furious.  A 
single  gun  was  mounted  on  the  after  deck  of  each 
vessel  and  the  gun  was  arranged  to  fire  only 
on  the  starboard  side.  No  heavily  armored 
turret  was  provided,  but  merely  a  light  housing 
to  shelter  the  gun. 

AN   ELECTRICALLY    STEERED    MOTOR-BOAT 

The  British  war-vessels  that  operated  in  the 
shallow  waters  off  the  coast  of  Flanders  were  a 
constant  source  of  annoyance  to  the  Germans. 
Because  of  the  shallow  water  it  was  seldom  pos- 
sible for  a  submarine  to  creep  up  on  them.  A 
U-boat  required  at  least  thirty-five  feet  of  water 
for  complete  submergence  and  it  did  not  dare 
to  attack  in  the  open.  This  led  the  Germans  to 
launch  a  motor-boat  loaded  with  high  explosive, 
which  was  steered  from  shore.  The  motor- 
boat  carried  a  reel  of  wire  which  connected  it 
with  an  operator  on  shore.  There  was  no  pilot 
in  the  boat,  but  the  helm  was  controlled  elec- 
trically by  the  man  at  the  shore  station.  As  it 
was  diffcult  for  the  helmsman  to  see  just  what 
his  boat  was  doing,  or  just  how  to  steer  it  when 
it  was  several  miles  off,  an  airplane  flew  high 


SURFACE  BOATS  309 

above  it  and  directed  the  helmsman,  by  radio- 
telegraphy,  how  to  steer  his  boat.  Of  course, 
radiotelegraphy  might  have  been  used  to 
operate  the  steering-mechanism  of  the  boat, 
but  there  was  the  danger  that  the  radio  oper- 
ators of  the  British  might  send  out  disturbing 
waves  that  would  upset  the  control  of  the  motor- 
boat,  and  so  direct  wire  transmission  was  used 
instead.  Fortunately,  when  the  Germans  tried 
this  form  of  attack,  an  alert  British  lookout  dis- 
covered the  tiny  motor-boat.  The  alarm  was 
given  and  a  lucky  shot  blew  up  the  boat  with 
its  charge  before  it  came  near  the  British  vessel. 


CHAPTER  XVI 
RECLAIMING  THE  VICTIMS  OF  THE  SUBMARINE 

NEARLY  fifteen  million  tons  of  shipping  lie 
at  the  bottom  of  the  sea,  sunk  by  German 
U-boats,  and  the  value  of  these  ships  with  their 
cargo  is  estimated  at  over  seven  billion  dollars. 
In  one  year,  1917,  the  loss  was  nearly  a  million 
dollars  a  day. 

Of  course  these  wrecks  would  not  be  worth 
anything  like  that  now,  if  they  were  raised  and 
floated.  Much  of  the  cargo  would  be  so  dam- 
aged by  its  long  immersion  in  salt  water  that  it 
would  be  absolutely  valueless,  but  there  are 
many  kinds  of  merchandise  that  are  not  injured 
in -the  least  by  water.  Every  ship  carries  a  cer- 
tain amount  of  gold  and  silver;  and  then  the 
ship's  hull  itself  is  well  worth  salving,  provided 
it  was  not  too  badly  damaged  by  the  torpedo 
that  sank  it.  Altogether,  there  is  plenty  of  rich 
treasure  in  the  sea  awaiting  the  salvor  who  is 
bold  enough  to  go  after  it. 

310 


VICTIMS  OF  THE  SUBMARINE         311 

To  be  sure,  not  all  of  the  U-boat's  victims 
were  sunk  in  deep  water.  Many  torpedoed  ves- 
sels were  beached  or  succeeded  in  reaching  shal- 
low water  before  they  foundered.  Some  were 
sunk  in  harbors  while  they  lay  at  anchor,  before 
the  precaution  was  taken  of  protecting  the  har- 
bors with  nets.  The  Allies  did  not  wait  for  the 
war  to  end  before  trying  to  refloat  these  vessels. 
In  fact,  during  the  war  several  hundred  ships 
were  raised  and  put  back  into  service.  A 
special  form  of  patch  was  invented  to  close 
holes  torn  by  torpedoes.  Electric  pumps  were 
built  which  would  work  under  water  and  these 
were  lowered  into  the  holds  of  ships  to  pump 
them  out.  The  salvors  were  provided  with 
special  gas-masks  to  protect  them  from  poison- 
ous fumes  of  decayed  matter  in  the  wrecks. 

Our  own  navy  has  played  an  important  part 
in  salvage.  Shortly  after  we  entered  the  war, 
all  the  wrecking-equipment  in  this  country  was 
commandeered  by  the  government  and  we  sent 
over  to  the  other  side  experienced  American  sal- 
yors,  provided  with  complete  equipment  of  appa- 
ratus and  machinery. 

The  majority  of  wrecks,  however,  are  found 
in  the  open  sea,  where  it  would  have  been  foolish 


312     INVENTIONS  OF  THE  GREAT  WAR 

to  attempt  any  salvage-operations  because  of  the 
menace  of  submarine  attack.  On  at  least  one 
occasion  a  salvage  vessel,  while  attempting  to 
raise  the  victims  of  a  submarine,  fell,  itself,  a 
prey  to  a  Hun  torpedo.  Now  that  this  menace 
has  been  removed,  such  vessels  as  lie  in  com- 
paratively shallow  water,  and  in  positions  not 
subject  to  sudden  tempests,  can  be  raised  by  the 
ordinary  methods;  or  if  it  is  impracticable  to 
raise  them,  much  of  their  cargo  can  be  reclaimed. 
However,  most  of  the  torpedoed  ships  lie  at 
such  depths  that  their  salvage  would  ordinarily 
be  despaired  of. 

IN    THE  DEPTHS   OF   THE   SEA 

It  will  be  interesting  to  look  into  conditions 
that  exist  in  deep  water.  Somehow  the  notion 
has  gone  forth  that  a  ship  will  not  surely  sink 
to  the  very  bottom  of  the  deep  sea,  but  on  reach- 
ing a  certain  level  will  find  the  water  so  dense 
that  even  solid  iron  will  float,  as  if  in  a  sea  of 
mercury,  and  that  here  the  ship  will  be  main- 
tained in  suspension,  to  be  carried  hither  and 
yon  by  every  chance  current.  Indeed,  it  makes 
a  rather  fantastic  picture  to  think  of  these  losl 
ships  drifting  in  endless  procession,  far  down 


VICTIMS  OP  THE  SUBMARINE          313 

beneath  the  cold  green  waves,  and  destined  to 
roam  forever  like  doomed  spirits  in  -a  circle  of 
Dante's  Inferno. 

But  the  laws  of  physics  shatter  any  such  illu- 
sion and  bid  us  paint  a  very  different  picture. 
Liquids  are  almost  incompressible.  The  differ- 
ence in  density  between  the  water  at  the  surface 
of  the  sea  and  that  at  a  depth  of  a  mile  is  almost 
insignificant.  As  a  matter  of  fact,  at  that  depth 
the  water  would  support  only  about  half  a 
pound  more  per  cubic  foot  than  at  the  surface. 
The  pressure,  however,  would  be  enormous. 
Take  the  Titanic,  for  instance,  which  lies  on  the 
bed  of  the  ocean  in  water  two  miles  deep.  It 
must  endure  a  pressure  of  about  two  long  tons 
on  every  square  inch  of  its  surface.  Long  be- 
fore the  vessel  reached  the  bottom  her  hull 
must  have  been  crushed  in.  Every  stick  of 
wood,  every  compressible  part  of  her  structure 
and  of  her  cargo,  must  have  been  staved  in  or 
flattened.  As  a  ship  sinks  it  is  not  the  water  but 
the  ship  that  grows  progressively  denser.  The 
Titanic  must  have  actually  gained  in  weight  as 
she  went  down,  and  so  she  must  have  gathered 
speed  as  she  sank. 

We  may  be  certain,  therefore,  that  every  vie- 


314      INVENTIONS  OF  THE  GREAT  WAR 

tim  of  Germany's  ruthless  U-boats  that  sank 
in  deep  water  lies  prone  upon  the  floor  of  the 
sea.  It  matters  not  how  or  where  it  was  sunk, 
whether  it  was  staggered  by  the  unexpected  blow 
of  the  torpedo  and  then  plunged  headlong  into 
the  depths  of  the  sea,  or  whether  it  lingered, 
mortally  wounded,  on  the  surface,  quietly 
settling  down  until  the  waves  closed  over  it. 
Theoretically,  of  course,  a  perfect  balance  might 
be  reached  which  would  keep  a  submerged  ves- 
sel in  suspension,  but  practically  such  a  condi- 
tion is  next  to  impossible.  Once  a  ship  has 
started  down,  she  will  keep  on  until  she  reaches 
the  very  bottom,  whether  it  be  ten  fathoms  or 
ten  hundred. 

A   SUBMARINE   GRAVEYARD 

Instead  of  the  line  of  wandering  specters, 
then,  we  must  conjure  up  a  different  picture, 
equally  weird — an  under-world  shrouded  in 
darkness;  for  little  light  penetrates  the  deep 
sea.  Here  in  the  cold  blackness,  on  the  bed  of 
the  ocean,  the  wrecks  of  vessels  that  once  sailed 
proudly  overhead  lie  still  and  deathly  silent- 
some  keeled  over  on  their  sides,  some  turned 


VICTIMS  OF  THE  SUBMARINE         315 

turtle,  and  most  of  them  probably  on  even  keel. 
Here  and  there  may  be  one  with  its  nose  buried 
deep  in  the  mud ;  and  in  the  -shallower  waters 
we  may  come  across  one  pinned  down  by  the 
stern,  but  with  its  head  buoyed  by  a  pocket  of 
air,  straining  upward  and  swaying  slightly  with 
every  gentle  movement  of  the  sea,  as  if  still 
alive. 

This  submarine  graveyard  offers  wonderful 
opportunities  for  the  engineer,  because  the  rais- 
ing of  wrecked  vessels  is  really  a  branch  of  en- 
gineering. It  is  a  very  special  branch,  to  be 
sure,  and  one  that  has  not  begun  to  receive  the 
highly  concentrated  study  that  have  such  other 
branches  as  tunneling,  bridge-construction,  etc. 
Nevertheless  it  is  engineering,  and  it  has  been 
said  of  the  engineer  that  his  abilities  are  limited 
only  by  the  funds  at  his  disposal.  Now  he  has 
a  chance  to  show  what  he  can  do,  for  there  are 
hundreds  of  vessels  to  be  salved  where  before 
there  was  but  one.  The  vast  number  of  wrecks 
in  deep  water  will  make  it  pay  to  do  the  work 
on  a  larger  and  grander  scale  than  has  been 
possible  heretofore.  Special  apparatus  that 
could  not  be  built  economically  for  a  single 


316     INVENTIONS  OF  THE  GREAT  WAR 

wreck  may  be  constructed  with  profit  if  a  num- 
ber of  vessels  demanding  similar  treatment  are 
to  be  salved. 

The  principal  fields  of  German  activities  were 
the  Mediterranean  Sea  and  the  waters  surround- 
ing the  British  Isles.  Although  the  submarine 
zone  covered  some  very  deep  water,  where  the 
sounding-lead  runs  down  two  miles  without 
touching  bottom,  obviously  more  havoc  could 
be  wrought  near  ports  where  vessels  were 
obliged  to  follow  a  prescribed  course,  and  so 
most  of  the  U-boat  victims  were  stricken  when 
almost  in  sight  of  land.  In  fact,  as  was  pointed 
out  in  a  previous  chapter,  it  was  not  until  ef- 
ficient patrol  measures  made  it  uncomfortable 
for  the  submarines  that  they  pushed  out  into  the 
open  ocean  to  pursue  their  nefarious  work. 
The  Lusitania  went  down  only  eight  miles  from 
Old  Head  of  Kinsale,  in  fifty  fathoms  of  water. 

If  we  draw  a  line  from  Fastnet  Rock  to  the 
Scilly  Islands  and  from  there  to  the  western- 
most extremity  of  France,  we  enclose  an  area 
in  which  the  German  submarines  were  particu- 
larly active.  The  soundings  here  run  up  to 
about  sixty  fathoms  in  some  places,  but  the  pre- 
vailing depth  is  less  than  fifty  fathoms.  In 


VICTIMS  OF  THE  SUBMARINE         317 

the  North  Sea,  too,  except  for  a  comparatively 
narrow  lane  along  the  Norwegian  coast — which, 
by  the  way,  marked  the  safety  lane  of  the  Ger- 
man blockade  zone — the  chart  shows  fifty 
fathoms  or  under.  If  our  salvors  could  reach 
down  as  far  as  that,  most  of  the  submarine 
victims  could  be  reclaimed.  But  fifty  fathoms 
means  300  feet,  which  is  a  formidable  depth 
for  salvage  work.  Only  one  vessel  has  ever 
been  brought  up  from  such  a  depth  and  that 
was  a  small  craft,  one  of  our  submarines,  the 
F-4,  which  sank  off  the  coast  of  Hawaii  four 
years  ago. 

DIFFERENT    WAYS   OF    SALVING   A    WRECK 

There  are  four  well-known  methods  of  rais- 
ing a  vessel  that  is  completely  submerged.  Of 
course,  if  the  ship  is  not  completely  submerged, 
the  holes  in  her  hull  may  be  patched  up,  and 
then  when  her  hull  is  pumped  out,  the  sea  itself 
will  raise  the  ship,  unless  it  be  deeply  embedded 
in  sand  or  mud.  If  the  vessel  is  completely 
submerged,  the  same  process  may  be  resorted 
to,  but  first  the  sides  of  the  hull  must  be  ex- 
tended to  the  surface  to  keep  the  water  from 
flowing  in  as  fast  as  it  is  pumped  out.  It  is 


318      INVENTIONS  OF  THE  GREAT  WAR 

not  usual  to  build  up  the  entire  length  of  the 
ship.  If  the  deck  is  in  good  condition,  it  may 
suffice  to  construct  coffer-dams  or  walls  around 
several  of  the  hatches.  But  building  up  the 
sides  of  a  ship,  or  constructing  coffer-dams  on 
the  ship's  deck  is  a  difficult  task,  at  best,  because 
it  must  be  done  under  water  by  divers. 

A  record  for  this  type  of  salvage  work  was 
established  by  the  Japanese  when  they  raised 
the  battle-ship  Mikasa  that  lay  in  some  eighty 
feet  of  water.  Her  decks  were  submerged  to  a 
depth  of  forty  feet.  It  is  doubtful  that  this 
salvage  work  could  be  duplicated  by  any  other 
people  of  the  world.  The  wonderful  patriot- 
ism and  loyalty  of  the  Japanese  race  were  called 
forth.  It  is  no  small  task  to  build  a  large  coffer- 
dam strong  enough  to  withstand  the  weight  of 
forty  feet  of  water,  or  a  pressure  of  a  ton  and  a 
quarter  per  square  foot,  even  when  the  work  is 
done  on  the  surface.  Perfect  discipline  and  or- 
ganized effort  of  the  highest  sort  were  required. 
Labor  is  cheap  in  Japan  and  there  was  no 
dearth  of  men  for  the  work.  Over  one  hundred 
divers  were  employed.  In  addition  to  the  cof- 
fer-dam construction  much  repair  work  was  nec- 
oessary.  Marvelous  acts  of  devotion  and  hero- 


VICTIMS  OF  THE  SUBMARINE 

ism  were  performed.  It  is  rumored  that  In 
some  places  it  was  necessary  for  divers  to  close 
themselves  in,  cut  their  air  supply-pipes  and 
seal  themselves  off  from  the  slightest  chance 
of  escape ;  and  that  there  were  men  who  actu- 
ally volunteered  to  sacrifice  their  lives  in  this 
way  for  their  beloved  country  and  its  young 
navy.  Where,  indeed,  outside  of  the  Land  of 
the  Rising  Sun  could  we  find  such  patriotic  de- 
votion ! 

A  second  salvage  method  consists  in  building 
a  coffer-dam  not  on  the  ship  but  around  it, 
and  then  pumping  this  out  so  as  to  expose  the 
ship  as  in  a  dry-dock.  Such  was  the  plan  fol- 
lowed out  in  recovering  the  Maine.  Obviously, 
it  is  a  very  expensive  method  and  is  used  only 
in  exceptional  cases,  such  as  this,  in  which  it 
was  necessary  to  make  a  post-mortem  examina- 
tion to  determine  what  caused  the  destruction 
of  the  vessel.  Neither  of  these  methods  of  sal- 
vage will  serve  for  raising  a  ship  sunk  in  deep 
water. 

RAISING   A   SHIP   OK    AIR 

A  salvage  system  that  has  come  into  promin- 
•noe  within  recent  years  consists  in  pumping 


320     INVENTIONS  OP  THE  GREAT  WAR 

air  into  the  vessel  to  drive  the  water  out,  thus 
making  the  boat  light  enough  to  float.  This 
scheme  can  be  used  only  when  the  deck  and 
bulkheads  of  the  boat  are  strongly  built  and 
able  to  stand  the  strain  of  lifting  the  wreck, 
and  when  the  hole  that  sank  the  vessel  is  in  or 
near  the  bottom,  so  as  to  allow  enough  air- 
space above  it  to  lift  the  boat.  The  work  of 
the  diver  in  this  case  consists  of  closing  hatches 
and  bulkhead  doors,  repairing  holes  in  the 
upper  part  of  the  hull,  and  generally  strength- 
ening the  deck.  It  must  be  remembered  that 
a  deck  is  built  to  take  the  strain  of  heavy 
weights  bearing  down  upon  it.  It  is  not  built 
to  be  pushed  up  from  beneath,  so  that  frequently 
this  method  of  salving  is  rendered  impractic- 
able because  the  deck  itself  cannot  stand  the 
strain. 

A  more  common  salvage  method  consists  in 
passing  cables  or  chains  under  the  wreck  and 
attaching  them  to  large  floats  or  pontoons. 
The  slack  in  the  chains  is  taken  up  when  the  tide 
is  low,  so  that  on  the  turn  of  the  tide  the  wreck 
will  be  lifted  off  the  bottom.  The  partially 
raised  wreck  is  then  towed  into  shallower  water, 
until  it  grounds.  At  the  next  low  tide,  the 


Climbing  into  an  Armored   Diving  Suit 


Lowering  an  Armored  Diver  into  the  Water 


A  Diver's  Sea  Sled  ready  to  be  towed  along  the  bed  of  the  sea 


The  Sea  Sled  on  Land  showing  the  forward  horizontal  and 
after  vertical  rudders 


VICTIMS  OF  THE  SUBMARINE         321 

slack  of  the  chains  is  again  taken  in,  and  at 
flood-tide  the  wreck  is  towed  nearer  land.  The 
work  proceeds  step  by  step,  until  the  vessel  is 
moved  inshore  far  enough  to  bring  its  decks 
awash ;  when  it  may  be  patched  up  and  pumped 
out.  Where  the  rise  of  the  tide  is  not  sufficient 
to  be  of  much  assistance,  hydraulic  jacks  or 
other  lifting-apparatus  are  used. 

SALVING  THE   U.    S.   SUBMARINE   F-4 

If  the  salvor  could  always  be  assured  of  clear 
weather,  his  troubles  would  be  reduced  a  hun- 
dredfold, but  at  best  it  takes  a  long  time 'to 
perform  any  work  dependent  upon  divers,  and 
the  chances  are  very  good  when  they  are  operat- 
ing in  an  unsheltered  spot,  that  a  storm  may 
come  up  at  any  time  and  undo  the  result  of 
weeks  and  months  of  labor.  This  is  what 
happened  when  the  submarine  F-4  was  salved. 
After  a  month  of  trying  effort  the  submarine 
was  caught  in  slings  hung  from  barges,  lifted 
two  hundred  and  twenty-five  feet,  and  dragged 
within  a  short  distance  of  the  channel  entrance 
of  the  harbor,  where  the  water  was  but  fifty 
feet  deep.  But  just  then  a  violent  storm  arose, 
which  made  the  barges  surge  back  and  forth  and 


322      INVENTIONS  OF  THE  GREAT  WAR 

plunge  so  violently  that  the  forward  sling  cut 
into  the  plating  of  the  submarine  and  crushed 
it.  The  wreck  had  to  be  lowered  to  the  bottom 
and  the  barges  cut  free  to  save  them  from  being 
smashed.  At  the  next  attempt  to  raise  the  F-4 
pontoons  were  again  used,  but  instead  of  be- 
ing arranged  to  float  on  the  surface,  they  were 
hauled  down  to  the  wreck  and  made  fast  directly 
to  the  hull  of  the  submarine.  Then  when  the 
water  was  forced  out  of  the  pontoons  with  com- 
pressed air,  they  came  up  to  the  surface,  bring- 
ing the  submarine  with  them.  In  this  way  all 
danger  of  damage  due  to  sudden  storms  was 
avoided  because  water  under  the  surface  is  not 
disturbed  by  storms  overhead;  and  when  the 
wreck  was  floated,  the  pontoons  and  submarine 
formed  a  compact  unit. 

While  this  method  of  salvage  seems  like  a 
very  logical  one  for  work  in  the  open  sea,  one 
is  apt  to  forget  how  large  the  pontoons  must 
be  to  lift  a  vessel  of  any  appreciable  size.  Not 
only  must  they  support  their  own  dead  weight, 
together  with  that  of  the  sunken  vessel,  but 
some  allowance  must  usually  be  made  for  drag- 
ging the  wreck  out  of  the  clutches  of  a  sandy  or 
muddy  bottom.  Imagine  the  work  of  building 


VICTIMS  OF  THE  SUBMARINE          323 

pontoons  large  enough  to  raise  the  Lusitania. 
They  would  have  to  have  a  combined  displace- 
ment greater  than  that  of  the  vessel  itself,  and 
they  would  have  to  be  so  large  that  they  would 
be  very  unwieldy  things  to  handle  in  a  seaway. 
It  is  for  this  reason  that  submarine  pontoons 
are  not  often  used  to  take  the  entire  weight  of 
the  vessel.  So  far  they  have  been  employed 
mainly  to  salve  small  ships  and  then  only  to  take 
a  portion  of  the  weight,  the  principal  work  be- 
ing done  by  large  wrecking-cranes.  Instead 
of  horizontal  pontoons  it  has  been  suggested  that 
vertical  pontoons  be  employed,  so  as  to  provide 
a  greater  lifting-power  without  involving  the 
use  of  enormous  unwieldy  units. 

Ships  are  not  built  so  that  they  can  be  picked 
up  by  the  ends.  Such  treatment  would  be  lia- 
ble to  break  their  backs  in  the  middle.  Were 
they  built  more  like  a  bridge  truss,  the  salvor's 
difficulties  would  be  materially  lessened.  It 
would  be  a  much  simpler  matter  to  raise  a  ves- 
sel with  pontoons  were  it  so  constructed  that 
the  chains  of  the  pontoon  could  be  attached  to 
each  end  of  the  hull.  But  because  a  ship  is 
built  to  be  supported  by  the  water  uniformly 
throughout  its  length,  the  salvor  must  use  a 


324      INVENTIONS  OF  THE  GREAT  WAR 

large  number  of  chains,  properly  spaced  along 
the  hull,  so  as  to  distribute  the  load  uniformly 
and  see  that  too  much  weight  does  not  fall  on 
this  or  that  pontoon. 

The  main  problem,  however,  is  to  get  hold  of 
the  wreck  and  this  requires  the  services  of 
divers,  so  that  if  there  were  no  other  limiting 
factor,  the  depth  to  which  a  diver  may  penetrate 
and  perform  his  duties  sets  the  mark  beyond 
which  salvage  as  now  conducted  is  impossible. 

A  common  diver's  suit  does  not  protect  the 
diver  from  hydraulic  pressure.  Only  a  flexible 
suit  and  a  thin  layer  of  air  separates  him  from 
the  surrounding  water.  This  air  must  neces- 
sarily be  of  the  same  pressure  as  the  surrtiund- 
ing  water.  The  air  that  is  pumped  down 
to  the  diver  not  only  serves  to  supply  his 
lungs,  but  by  entering  his  blood  transmits  its 
pressure  to  every  part  of  his  anatomy.  As 
long  as  the  external  pressure  is  equalized  by 
a  corresponding  pressure  within  him,  the  diver 
experiences  no  serious  discomfort.  In  fact, 
when  the  pressure  is  not  excessively  high  he 
finds  it  rather  exhilarating  to  work  under  such 
conditions;  for,  with  every  breath,  he  takes 
in  an  abnormal  amount  of  oxygen.  When 


( C)  International  Film  Service 

The  Diving  Sphere  built  for  Deep  Sea  Salvage  Operations 


o 


VICTIMS  OF  THE  SUBMARINE         325 

he  returns  to  the  surface  he  realizes  that 
he  has  been  working  under  forced  draft.  He 
is  very  much  exhausted  and  he  is  very  hungry. 
It  takes  a  comparatively  short  time  to  build 
up  the  high  internal  pressure,  which  the  diver 
must  have  in  order  to  withstand  the  pressure  of 
the  water  outside,  but  it  is  the  decompression 
when  he  returns  to  the  surface  that  is  attended 
with  great  discomfort  and  positive  danger.  If 
the  decompression  is  not  properly  effected,  the 
diver  will  suffer  agonies  and  even  death  from 
the  so-called  "Caisson  Disease." 

A   HUMAN    SODA-WATER   BOTTLE 

We  know  now  a  great  deal  more  than  we 
used  to  know  about  the  effect  of  compressed 
air  on  the  human  system,  and  because  of  this 
knowledge  divers  have  recently  descended  to 
depths  undreamed  of  a  few  years  ago.  "When 
a  diver  breathes  compressed  air,  the  oxygen  is 
largely  consumed  and  exhaled  from  the  lungs 
in  the  form  of  carbon-dioxide,  but  much  of  the 
nitrogen  is  dissolved  in  the  blood  and  does  not 
escape.  However,  like  a  bottle  of  soda-water, 
the  blood  shows  no  sign  of  the  presence  of  the 
gas  as  long  as  the  pressure  is  maintained.  But 


326      INVENTIONS  OF  THE  GREAT  WAR 

on  a  sudden  removal  of  the  pressure,  the  blood 
turns  into  a  froth  of  nitrogen  bubbles,  just  as 
the  soda-water  froths  when  the  stopper  of  the 
bottle  is  removed.  This  froth  interrupts  the 
circulation.  The  release  of  pressure  is  felt 
first  in  the  arteries  and  large  veins.  It  takes 
some  time  to  reach  all  the  tiny  veins,  and  serious 
differences  of  pressure  are  apt  to  occur  that 
often  result  in  the  rupture  of  blood-ves- 
sels. The  griping  pains  that  accompany  the 
"Caisson  Disease'7  are  excruciating.  The  only 
cure  is  to  restore  the  blood  to  its  original  pres- 
sure by  placing  the  patient  in  a  hospital  lock, 
or  boiler-like  affair,  where  compressed  air  may 
be  admitted;  and  then  to  decompress  the  air 
very  slowly. 

It  is  possible  to  relieve  the  pressure  in  a 
bottle  of  soda-water  so  gradually  that  the  gas 
will  pass  off  without  the  formation  of  visible 
bubbles,  and  that  is  what  is  sought  in  decom- 
pressing a  diver.  After  careful  research  it  has 
been  found  that  the  pressure  may  be  cut  down 
very  quickly  to  half  or  even  less  of  the  original 
'amount,  but  then  the  diver  must  wait  for  the 
decompression  to  extend  to  the  innermost  re- 


VICTIMS  OF  THE  SUBMARINE         327 

cesses  of  his  being  and  to  all  the  tiny  capillaries 
of  his  venous  system. 

In  the  salvage  of  the  F-4  a  diver  went  down 
306  feet,  and  remained  on  the  bottom  half  an 
hour.  The  pressure  upon  him  was  135  pounds 
per  square  inch,  or  about  145  tons  on  the  surface 
of  his  entire  body.  Some  idea  of  what  this 
means  may  be  gained  if  we  consider  that  the 
tallest  office  building  in  the  world  does  not  bear 
on  its  foundations  with  a  greater  weight  than 
215  pounds  to  the  square  inch  or  only  about  50 
per  cent  more  than  the  crushing  pressure  this 
diver  had  to  endure. 

It  took  the  diver  a  very  short  time  to  go  down. 
On  coming  up  he  proceeded  comparatively 
rapidly  until  he  reached  a  depth  of  100  feet. 
There  he  found  the  bottom  rung  of  a  rope 
ladder.  On  it  he  was  obliged  to  rest  for  several 
minutes  before  proceeding  to  the  next  rung. 
The  rungs  of  this  ladder  were  10  feet  apart,  and 
on  each  rung  the  diver  had  to  rest  a  certain 
length  of  time,  according  to  a  schedule  that  had 
been  carefully  worked  out.  At  the  top  rung, 
for  instance,  only  10  feet  from  the  surface,  he 
was  obliged  to  wait  forty  minutes.  In  all,  it 


328      INVENTIONS  OF  THE  GREAT  WAR 

took  him  an  hour  and  forty-five  minutes  to  come 
up  to  the  surface.  The  decompression  was 
complete  and  he  -suffered  no  symptoms  of  the 
" Caisson  Disease/'  But  he  was  so  exhausted 
from  his  efforts  that  he  was  unfit  for  work  for 
several  days.  Yet  the  operations  that  he  per- 
formed at  the  depth  of  300  feet  would  not  have 
taken  more  than  a  few  minutes  on  the  surface. 

A   SUBMARINE   REST-CHAMBER 

The  Germans  have  paid  a  great  deal  of  atten- 
tion to  deep-diving  operations,  and  no  doubt 
while  their  U-boats  were  sinking  merchant  ships 
German  salvors  were  anticipating  rich  harvests 
after  hostilities  ended.  One  scheme  they 
developed  was  a  submarine  rest-chamber  which 
could  be  permanently  located  on  the  bottom  of 
the  sea  close  to  the  point  where  the  salvage 
operations  were  to  take  place.  This  chamber 
consists  of  a  large  steel  box  which  is  supplied 
with  air  from  the  surface  and  in  which  divers 
may  make  themselves  comfortable  when  they 
need  a  rest  after  arduous  work.  Entrance  to 
the  chamber  is  effected  through  a  door  in  the 
floor.  The  pressure  of  the  air  inside  prevents 
the  water  from  rising  into  the  chamber  and 


VICTIMS  OF  THE  SUBMARINE         329 

flooding  it.  From  this  submarine  base  the 
divers  may  go  out  to  the  wreck,  either  equipped 
with  the  ordinary  air-tube  helmets  or  with  self- 
regenerating  apparatus  which  makes  them  in- 
dependent of  an  air-supply  for  a  considerable 
period  of  time.  When  the  diver  has  worked  for 
an  hour  or  two,  or  when  he  is  tired,  he  may  re- 
turn to  this  chamber,  remove  his  helmet,  eat  a 
hearty  meal,  take  a  nap  if  he  needs  it,  and  then 
return  to  the  salvage  work  without  going 
through  the  exhausting  operation  of  decom- 
pressing. 

CUTTING    METAL   UNDER   WATEE   WITH 
A   TOECH 

The  work  of  the  diver  usually  consists  of  far 
more  than  merely  passing  lines  under  a  sunken 
hull.  It  is  constantly  necessary  for  him  to  cut 
away  obstructing  parts.  He-  must  .sometimes 
use  blasting-power.  Pneumatic  cutting-tools 
frequently  come  into  play,  but  the  Germans  -have 
lately  devised  an  oxy-hydrogen  torch  for  under- 
water use,  with  which  the  diver  can  cut  metal 
by  burning  through  it.  This  is  a-ccomplished 
by  using  a  cup- shaped  nozzle  through  which  a 
blast  of  air  is  projected  under  such  pressure 


330      INVENTIONS  OF  THE  GREAT  WAR 

that  it  blows  away  the  water  over  the  part  to  be 
cut.  The  oxygen  and  hydrogen  jets  are  then 
ignited  electrically,  and  the  work  of  cutting  the 
metal  proceeds  in  the  hole  in  the  water  made  by 
the  air-blast.  A  similar  submarine  torch  has 
recently  been  developed  by  an  American  salvage 
company.  It  was  employed  successfully  in 
cutting  drainage-holes  in  the  bulkheads  of  the 
St.  Paul,  which  was  raised  in  New  York  Harbor 
in  the  summer  of  1918. 

EXPLORING    THE    SEA    BOTTOM    IN    A    DIVERTS    SLED 

The  diver's  sled  is  still  another  interesting 
German  invention.  It  is  a  sled  provided  with 
vertical  and  horizontal  rudders,  which  is  towed 
by  means  of  a  motor-boat  at  the  surface.  The 
diver,  seated  on  the  sled,  and  provided  with  a 
self-contained  diving-suit,  can  direct  the  motor- 
boat  by  telephone  and  steer  his  sled  up  and 
down  and  wherever  he  chooses.  And  so  with- 
out any  physical  exertion,  he  can  explore  the 
bottom  of  the  sea  and  hunt  for  wrecks. 

ARMORED   DIVING-SUITS 

From  time  to  time  attempts  have  been  made 
to  construct  a  diver's  suit  that  will  not  yield 


VICTIMS  OF  THE  SUBMARINE         331 

to  the  pressure  of  the  sea,  so  that  the  diver  will 
not  be  subjected  to  the  weight  of  the  water 
about  him,  but  can  breathe  air  at  ordinary 
atmospheric  pressure.     Curious  armor  of  steel 
has  been  devised,  with  articulated  arms  and 
legs,  in  which  the  diver  is  completely  encased. 
With  the  ordinary  rubber  suit,  the  diver  usually 
has  his  hands  bare,  because  he  is  almost  as  de- 
pendent upon  the  sense  of  touch  as  a  blind  man. 
But  where  the  pressure  mounts  up  to  such  a 
high  degree  that  a  metal  suit  must  be  used,  no 
part  of  the  body  may  be  exposed.    If  a  bare 
hand  were  extended  out  of  the  protecting  armor 
it  would  immediately  be  mashed  into  a  pulp  and 
forced  back  through  the  opening  in  the  arms  of 
the  suit.     The  best  that  can  be  done,  then,  is 
to  furnish  the  arms  of  the  suit  with  hooks  or 
tongs  or  other  mechanical  substitutes  for  hands 
which  will  enable  the  diver  to  make  fast  to  the 
wreck  or  various  parts  of  it. 

But  if  a  diver  feels  helpless  in  the  bag  of  a 
suit  now  commonly  worn,  what  would  he  do 
when  encased  in  a  steel  boiler;  for  that  is 
virtually  what  the  armored  suit  is !  A  common 
mistake  that  inventors  of  armor  units  have 
made  is  to  fail  to  consider  the  effects  of  the 


332      INVENTIONS  OF  THE  GREAT  WAR 

enormous  hydraulic  pressure  on  the  joints  of 
the  suit.  In  order  to  make  them  perfectly  tight, 
packings'  must  be  employed,  and  these  are  liable 
to  be  so  jammed  by  the  hydraulic  pressure  that 
it  is  well  nigh  impossible  to  articulate  the  limbs. 
Again,  the  construction  of  the  suit  should  be 
such  that  when  a  limb  is  Hexed  it  would  not  dis- 
place any  more  water  than  when  in  an  extended 
position,  and  vice  versa.  A  diver  may  find  that 
he  cannot  bend  his  arm,  because  in  doing  so  he 
would  expand  the  cubical  content  of  his  armor 
by  a  few  cubic  inches,  and  to  make  room  for  this 
increment  of  volume  it  would  bo  necessary  for 
him  to  lift  several  hundred  pounds  of  water. 
The  hydraulic  pressure  will  reduce  the  steel  suit 
to  its  smallest  possible  dimensions,  which  may 
result  either  in  doubling  up  the  members  or  ex- 
tending them  rigidly. 

But  these  difficulties  are  not  insuperable. 
There  is  no  reason  why  a  steel  manikin  cannot 
be  constructed  with  a  man  inside  to  direct  its 
movements. 

THK  SALVOR'S  SUBMARINE 

Other  schemes  have  been  devised  to  relieve 
the  diver  of  abnormally  high  air-pressure. 


VICTIMS  OF  THE  SUBMARINE         333 

One  plan  is  to  construct  a  large  spherical  work- 
ing-chamber strong  enough  to  withstand  any 
hydraulic  pressure  that  might  be  encountered. 
This  working-chamber  is  equipped  with  heavy 
glass  ports  through  which  the  workers  can  ob- 
serve their  surroundings  in  the  light  of  an 
electric  search-light  controlled  from  within  the 
chamber.  The  sphere  is  to  be  lowered  to  the 
wreck  from  a  barge,  with  which  it  will  be  in  tele- 
phonic communication  and  from  which  it  will  be 
supplied  with  electric  current  to  operate  various 
electrically  driven  mechanisms.  By  means  of 
electromagnets  this  sphere  may  be  made  fast  to 
the  steel  hull  of  the  vessel  and  thereupon  an 
electric  drill  is  operated  to  bore  a  hole  in  the 
ship  and  insert  the  hook  of  a  hoisting-chain. 
This  done,  the  sphere  would  be  moved  to  an- 
other position,  as  directed  by  telephone  and  an- 
other chain  made  fast.  The  hoisting-chains  are 
secured  to  sunken  pontoons  and  after  enough 
of  the  chains  have  been  attached  to  the  wreck 
the  pontoons  are  pumped  out  and  the  wreck  is 
raised. 

It  is  a  pity  that  ship-builders  have  not  had 
the  forethought  to  provide  substantial  shackles 
at  frequent  intervals  firmly  secured  to  the  f ram- 


334      INVENTIONS  OF  THE  GREAT  WAR 

ing.  A  sunken  vessel  is  really  a  very  difficult 
object  to  make  fast  to  and  the  Patent  Office 
has  recorded  many  very  fantastic  schemes  for 
getting  hold  of  a  ship's  hull  without  the  use  of 
divers.  One  man  proposes  the  use  of  a  gigantic 
pair  of  ice-tongs;  and  there  have  been  no  end 
of  suggestions  that  lifting-magnets  be  em- 
ployed, but  no  one  who  has  any  idea  of  how 
large  and  how  heavy  such  magnets  must  be 
would  give  these  suggestions  any  serious  consid- 
eration. 

But,  after  all,  the  chief  obstacle  to  salvage  in 
the  open  sea  is  the  danger  of  storms;  months  of 
preparation  and  thousands  of  dollars'  worth  of 
equipment  may  be  wiped  out  in  a  moment. 

FIOHTINO   THE    WAVES    WITH    AIR 

However,  there  has  been  another  recent  de- 
velopment which  may  have  a  very  important 
bearing  on  this  problem  of  deep-sea  salvage 
work.  It  has  often  been  observed  that  a  sub- 
merged reef,  twenty  or  thirty  feet  below  the 
surface,  may  act  as  a  breakwater  to  stop  the 
storming  waves.  Ail  inventor  who  studied  this 
phenomenon  arrived  at  the  theory  that  the 
reefs  set  up  eddies  in  the  water  which  break 


VICTIMS  OF  THE  SUBMARINE         335 

up  the  rhythm  of  the  waves  and  convert  them 
into  a  smother  of  foam  just  above  the  reef. 
Thereupon  he  conceived  the  idea  of  performing 
the  same  work  by  means  of  compressed  air.  He 
laid  a  pipe  on  the  sea  bottom,  forty  or  fifty 
feet  below  the  surface,  and  pumped  air  through 
it.  Just  as  he  had  expected,  the  line  of  air 
bubbles  produced  exactly  the  same  effect  as  the 
submerged  reef.  They  set  up  a  vertical  current 
of  water  which  broke  up  the  waves  as  soon  as 
they  struck  this  barrier  of  air. 

The  "  pneumatic  breakwater, "  as  it  is  called, 
has  been  tried  out  on  an  exposed  part  of  the 
California  coast,  to  protect  a  long  pier  used  by 
an  oil  company.  It  has  proved  so  satisfactory 
that  the  same  company  has  now  constructed  a 
second  breakwater  about  another  pier  near  by. 
There  is  no  reason  why  a  breakwater  of  this 
sort  should  not  be  made  about  a  wreck  to  protect 
the  workers  from  storms.  Where  the  water  is 
very  deep,  it  would  not  be  necessary  to  lay  the 
compressed-air  pipe  on  the  bottom,  but  it  could 
be  carried  by  buoys  at  a  convenient  depth. 

Summing  up  the  situation,  then,  there  are 
two  serious  bars  to  the  successful  salvage  of 
ships  sunk  in  the  open  sea — the  wild  f  ury  of  the 


336     INVENTIONS  OF  THE  GREAT  WAR 

waves  on  the  surface;  and  the  silent,  remorse- 
less pressure  of  the  deep.  The  former  is  the 
more  to  be  feared;  and  if  the  waves  really  can 
be  calmed,  considerably  more  than  half  the 
problem  is  solved.  As  for  the  pressure  of  the 
sea,  it  can  be  overcome,  as  we  have  seen,  either 
by  the  use  of  special  submarine  mechanisms, 
or  of  man-operated  manikins  or  even  of  un- 
armored  divers.  We  have  reached  a  very  in- 
teresting stage  in  the  science  of  salvage,  with 
the  promise  of  important  developments.  Fifty 
fathoms  no  longer  seems  a  hopeless  depth. 

Even  in  times  of  peace  the  sea  exacts  a  dread- 
ful toll  of  lives  and  property.  Before  the  war 
the  annual  loss  by  shipwreck  around  the  British 
Isles  alone  was  estimated  at  forty  five  million 
dollars.  But  the  war,  although  it  was  fright- 
fully destructive  to  shipping,  may  in  the  long 
run  save  more  vessels  than  it  sank;  for  it  has 
given  us  sound-detectors  which  should  remove 
the  danger  of  collisions  in  foggy  weather,  and 
the  wireless  compass,  which  should  keep  ships 
from  running  off  the  course  and  on  the  rocks. 
And  now,  if  salvage  engineering  develops  as  it 
should,  the  sea  will  be  made  to  give  up  not  only 


VICTIMS  OF  THE  SUBMARINE         337 

much  of  the  wealth  it  swallowed  during  the  war, 
but  also  many  of  the  rich  cargoes  of  gold  and 
silver  it  has  been  hoarding  since  the  days  of  the 
Spanish  galleon. 


INDEX 


Air,  fighting  wave*,  334 

raiting  ship,  on,  310 

war  in,  123 
Airplane,  ambulance,  146 

armored,  139 

artillery  •potting,  131 

camera.   173 

cartridge*,  131 

clause*  of  work,  127 

fighting  among  clouds,   137 

flying  boaU.  144 

gMolene  tank.  130 

giant,  132 

hospital,    140 

launching  from  whip,  303 

Liberty  motor,  142 

scouting,  125 

scout*.   128 

speed  of,   134 

spotting,   177 

training  *  potters,  180 

wireless  telephone,    194 

See  al*o  Seaplane 
Ambulance  airplane,  146 
Armored    diving  suit,    330 
Arms  and  armor,   1 1 1 
Artillery,  hand,  23 
Atmosphere,  shooting  beyond, 

64 
A  ud  ion,   185 

Balloon,  Blimp,  260 
helium,  164 
historical,   148 
hydrogen,    150 


Balloon,  kite,  174 

principles,  150 

record  flight,  66 
Barbed  wire,  15 

cylinders,  17 

gate,  trench,  0 

gates  through,  15 

shelling,  16 
Barge    for    towing    seaplanss, 

302 
Barrage,  grenade,  27 

mine,  292 

Battle-fields,  miniature,  180 
Blimp,  260 

Blisters  on  ships,  307 
Boats,  electric,  308 

Eagle,  301 

flying,  144 

surface,  298 
Bomb*      to     destroy      barbsd 

wire,  16 

Breakwater,  pneumatic,  335 
Browning,  John  M.,  56 
Buildings,  shadowless,  227 

Caisson  disease,  325 
Caliber,  68 

Camera,  airplane,   173 
Camouflage   and   camoufleurs, 
211 

buildings,  227 

grass,  229 

horse,  223 

land,  222 

roads,  225 


339 


840 


INDEX 


Camouflage.  »hip«.  21  1 

Cartridge,  aircraft  gunt,  13! 

CatapuiU,  30 

Caterpillar  tractor,  109 

Caret.  8 

Coffer-dam,  talragt,  318 

Color,  analy/ing,  229 

•creeni.  229 
Com  pa  u,  irirele**,  201 
Convoy,  267 
Countermine*.  1? 

Deep  M-».  condition*  in,  312 
Drep  water  diving.   327 
Depth  bom»»t.  205 
Devil's  egfr»,  j?fl 
Die««t  engine.  240 
Direction-fin  ier.  205 
Dirigible.  »««•  <  »li  «  n 

DifAftr,     it1""     ••      X  '. 

Di\rr.  arm!  red   auit.  33O 


Fort*,  machine  gun,  68 
FUM,  grenade.  28 


rr%t 

•  led.   3.10 

•ulmnnr.e  torch.  3'^ 

•;iit.  3*4 
Diving,  dr  p.  324 

record  d*-;,th.  327 
Duck  '*.-ard».   V 


Dumtr.v       head*      of       papier 
mich*.  13 

K*j?!e  t-xit*.  3'»1 
Kgg-la>:r.g  »u.:r.arine».  2b7 
Kgg».  Dev;;^.  276 
Klcctr;c  mutor  >j«t,  30» 
rlngine.  Du-»ei,  240 

Kip  Id  punt.  81 
Fire  broom,   105 
liquid,  103 


.  92 


Ga»,  85 

American.  102 
Ga*  attack, 

fir.t.  89 
Ga*.  chbrine,  87 

dipho^grne,  98 

•    ••-..•  a'  •  jr   raU.  94 

grer.ade*.  20 

h-'i-  m.   104 

hydrcgett.   1AO 

lock.  07 

rr«»    *    '  '* 

mu»!ard.  98 

pho«grne.  1*3 

pouring   ....r  water.  88 

•hril.  66 

ancej;:^-.  9H 

tear.    DA 

Turr.il  ;r.g.  9H 


Ga^-lrr.r  *ar.k.  airplane,  130 
Gate.  •  a-  «  i  wire,  trench.  9 
Gate*  ihrouxh  'ar  *•;  wire, 

15 

Gat  ling  gun.  43 
<•<•„•••'    '•'r».;r-.r.  Ridgt,  19 
«.  ."*    non-thaf.enng.    100 
(»rapne!  th«]l.  16 
Graveyard.  •ubmartM,  314 
Grrr.i'>.  dt»k-«haped.  33 

fuM-.  2§ 

g»».  2C 

bruth.  34 

h:«*cn-  of.  23 

Mint,*29 

pararh::!e.   31 

range  of,  25 

rtrV,  2? 

throwing  implement,  27 


INDEX 


341 


Grenade,  wind-vane  safety  de- 
vice, 32 
Gun,  aircraft,  131 

American,  60-mile,  63 

big,  hiding,  226 

caliber,  68 

disappearing,  77 

double-end,  145 

18- inch,  monitors,  906 

elastic,  73 

field.  81 

42-centimeter,  79 

how  made,  76 

120-mile,  70 

long  range,  Herman,  62 

non- recoil,   145 

on  submarine,  249 

16  inch,  coa«t  defense,  78 

Skoda.  HI 

spotting  by  »»ound,   181 

three-»e^onJ  life,  73 

12-inch,  submarine.  251 

way*    of    increasing    range, 
67 

wire  wound,  70 

Hand-grenade,    see    Grenade 
Heiivxn.    164 
Ho*pital,    airplane,    147 
Hori/on,  seeing  beyond,  219 
Howitzer,  79 
Hush  ships,  304 
Hydroaeroplanes,      *e«      Sea- 
planes 

Hydrogen,  weight  of,  150 
Hydrophone,  270 

Illusion*,  optical,  215 

Kilometer,  length  in  miles,  6 
Kite  balloons,   174 
Kite,  water,  283 


Liberty  motor,  142 
Liquid-fire,  103 
Locomotives,  gasolene,  10 
Lutitania,  316 

Machine-gun,  112 

airplane,  127 

Benet-Mercie,  52 

Browning,  53 

Colt,  44 

forts,  58 

Galling,  43 

history.  41 

Hotchkiss,  49 

Lewis,  50 

Maxim,  42 

water-jacket,  47 

worth  in  rifles,  58 
Machine-rifle,  "»5 
Magnets,  lilting,  salvage.  334 
Map-,    making    with    camera, 

175 

Marr".  flr*t  battle  of,  4 
Me*«ines  Ridge,  mine,   19 
Metal -cutting     under     water, 

329 
Microphone   detectors,   mines, 

18 

Mine-field,  North  Sea,  290 
Mine  laying,  North  Sea,  292 
Mine-laying  submarine,  287 
Mine  railroad,  294 
Mine-sweeping,  281 
Mines,  276 

anchored,  278 

and  countermines,  17 

automatic  sounding,  278 

drift  of,  285 

electric,  277 

floating,  284 

Messines  Ridge,  19 


342 


INDEX 


pararane*.  288 
Monitor*.  306 
Mortars,  79 

depth  bomb,  266 
flying,  23 
Mortar*.     8e«     alao     Trench 

mortar* 
Mother-ahip*     for     airplane*. 

Motor- boat,  electric.  308 

aea  Tank.  299 
Motor  torpedo  boat*,  296 
Mystery  *hip«.  220 

Net,  North  Sea.  290 

Ocean  current*.  286 
Optical  illusion*.  21ft 
Oxy  hydrogen     torch.     *ubm* 
rine.  329 

Paint  in  war.  209 
Papier  mach*  head*.   13 
P*pier  mAche  hor*e.  223 
Parachute.  175 

gren*de.  31 

•earchltght  *hell.  84 
Paravane*.   288 
Peri«rupe.  »ubmartne,  244 

trench.   1 1 
Pill  boxen.  59- 

Pneumatic  breakwater,  335 
Pontoon*.  »alvBge,  320 
Propeller,    "hooting    through. 
136 

Radio.  *ee  Wirele** 
Kailnmd.  mine.  294 
Railway*,  trench.    10 
Ranjre-flndcr.    170 
Rang?,  getting  the.  169 


Range  of  gun*,  increasing.  67 
Range,  torpedo.  213 
Rat*,  freeing  Kenche*  of,  94 
Rifle  grenade,  t8 

•afety  device.  32 
Rifle,  machine.  56 
Rifle  *tand.  fixed.  14 
Road*,  camouflage,  226 

Salvage.  310 

diving.  324 

ice-tong*.  334 

lifting  magnet*.  314 

method*.  317 

pneumatic.  319 

puntoun*.  320 

»hacklr«  on  »htp«.  333 

•ubmarine   K  4.  321 

•ubmarine  *phere.  332 
Scouu.  airplane,   12H 
Sea.  deep,  condition*.  312 
Sra  gull*  finding  •ubmarina*. 

25H 
S«a  lion*  locating  •ubmarine*. 

.     • 

S*a  tank.  299 
Seaplane.    143 

automatic.  145 

•ubmarine  patrol,  259 

torpedo.  145 

towing  bar ?r«.   3<rj 
Search  light  *heli.  H4 
Shackle*.  *a)vaK«.  333 
ShadowlcA*  building*.  227 
Shell.  ga«.  115 

grapnel.   16 

•earch  li^ht.  84 

•hrapnrl.  83 

Stoke*  mortar.  39 
Shield  on  wheel*.    114 
Ship*,  airplane.  3U4 


INDEX 


343 


Ships,  blisters,  307 

camouflage,  211 

"clothes-line,"  220 

convoy,  267 

hush,  304 

making  visible,  230 

monitors,  306 

mystery,  220 

railroads  on,  294 

sunk  by  submarines,  310 
Ship*,  see  also  Salvage 
Shrapnel  shell,  83 
Sled,  submarine,  330 
Smoke  screen,  262 
Sniper,  locating,  13 
Sniperscopes,  12 
Sound,  detecting  submarines, 

269 

Sound  detector*,  mines,  18 
Sound,  spotting  by,   181 
Sphere,     salvor's     submarine, 

332 

Spotting  by  sound,  Iftl 
Spotting  gun-fire,  177 
Submarine,  blindness,  '244 

chasers.  255 

construction,  234 

depth  bombs.  265 

egg-laying,  287 

engines,  246 

F4,  salving,  321 

getting  be»t  of,  253 

graveyard,  314 

guns  on,  249 

history,  232 

hydrophone,  270 

mine-field,  290 

mine-laying,  287 

net,  290 

oil-tank,  236 

periscope,  244 


Submarine,     reclaiming     vic- 
tims of,  310 

rest  chamber,  328 

saJvage  vessel,  332 

sea-gulls,  258 

sea-lion*,  259 

seaplanes,  259 

ships  sunk,  310 

sled,  330 

steam-driven,  250 

torch,  329 

torpedo.  246 

12-inch  gun,  251 

vs.  submarine,  269 
Super-gun*,  62 


Tank,   107 

American,   122 

flying,  139 

French,  119 

(ierman,  120 

one-man,  114 

sea,  299 

small,  121 

Telegraphy,  rapid,   199 
Telephone,  New  York  to  San 
Francisco,   186 

wirelesH.   178 
Titanic,  :H4 

TNT   (trinitrotoluol),  18 
Torch,  submarine,  329 
Torpedo,  299 

boats,  motor,  298 

electrically  steered,  108 

construction,  246 

getting  range,  213 

proof  ships,  306 

seaplane,  145 

Towing-barge,   seaplane,   302 
Trajectory,  22 


344 


INDEX 


Trench,  gas-lock,  07 
Trench  mortar,  36 

pneumatic,  37 

Stoke*.  38 
Trench  railway*,  10 
Trench  warfare,  4 
Trenches,  21 

barbed  wire  gate*,  0 

duck- board*,  9 
Tunnel*,  mine*,  17 

to  obaenration  poet*,  12 

U-boat*,  *ee  Submarine* 
Village*,  underground,  7 

Walking  machine.  108 

War,  paint.  209 

Water  kite*.  283 

Wave*,  fighting  with  air.  334 


Wirele**  compass,  201 

*pj  detector,  200 
Wirele**  telegraph,  rapid,  199 
Wirele**  telegraphy  explained. 

188 
Wirele**  telephone,   178 

airplane,  184 
Wirele**  telephony  acroat  At- 

lantic, 198 
Woolworth    Building,    falling 

from,  135 
Wreck*.  *ee  Salvage 


Zeppelin  and   Lowe's 

140 
Zeppelin     balloon,     construc- 

tion. 156 
Zeppelin,  suspended  obeerver, 

162 

Zeppelin's    failure* 
154 


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